diff --git a/mailpoet/composer.json b/mailpoet/composer.json
index dc00f869f9..d21635c1d7 100644
--- a/mailpoet/composer.json
+++ b/mailpoet/composer.json
@@ -42,7 +42,8 @@
   "autoload": {
     "classmap": [
       "lib-3rd-party",
-      "vendor-prefixed"
+      "vendor-prefixed",
+      "vendor/mailpoet/email-editor/src"
     ],
     "files": [
       "lib/exceptions.php",
diff --git a/mailpoet/lib/AdminPages/Pages/EmailEditor.php b/mailpoet/lib/AdminPages/Pages/EmailEditor.php
index 72939fb476..36e4f12c29 100644
--- a/mailpoet/lib/AdminPages/Pages/EmailEditor.php
+++ b/mailpoet/lib/AdminPages/Pages/EmailEditor.php
@@ -6,8 +6,8 @@ use MailPoet\API\JSON\API;
 use MailPoet\Config\Env;
 use MailPoet\Config\Installer;
 use MailPoet\Config\ServicesChecker;
-use MailPoet\EmailEditor\Engine\SettingsController;
-use MailPoet\EmailEditor\Engine\ThemeController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
+use MailPoet\EmailEditor\Engine\Theme_Controller;
 use MailPoet\EmailEditor\Integrations\MailPoet\EmailEditor as EditorInitController;
 use MailPoet\Newsletter\NewslettersRepository;
 use MailPoet\Settings\SettingsController as MailPoetSettings;
@@ -18,9 +18,9 @@ use MailPoet\WP\Functions as WPFunctions;
 class EmailEditor {
   private WPFunctions $wp;
 
-  private SettingsController $settingsController;
+  private Settings_Controller $settingsController;
 
-  private ThemeController $themeController;
+  private Theme_Controller $themeController;
 
   private CdnAssetUrl $cdnAssetUrl;
 
@@ -34,11 +34,11 @@ class EmailEditor {
 
   public function __construct(
     WPFunctions $wp,
-    SettingsController $settingsController,
+    Settings_Controller $settingsController,
     CdnAssetUrl $cdnAssetUrl,
     ServicesChecker $servicesChecker,
     SubscribersFeature $subscribersFeature,
-    ThemeController $themeController,
+    Theme_Controller $themeController,
     MailPoetSettings $mailpoetSettings,
     NewslettersRepository $newslettersRepository
   ) {
diff --git a/mailpoet/lib/Config/Initializer.php b/mailpoet/lib/Config/Initializer.php
index b333540f52..dc7b7bf198 100644
--- a/mailpoet/lib/Config/Initializer.php
+++ b/mailpoet/lib/Config/Initializer.php
@@ -11,7 +11,7 @@ use MailPoet\Automation\Integrations\MailPoet\MailPoetIntegration;
 use MailPoet\Automation\Integrations\WooCommerce\WooCommerceIntegration;
 use MailPoet\Cron\CronTrigger;
 use MailPoet\Cron\DaemonActionSchedulerRunner;
-use MailPoet\EmailEditor\Engine\EmailEditor;
+use MailPoet\EmailEditor\Engine\Email_Editor;
 use MailPoet\EmailEditor\Integrations\Core\Initializer as CoreEmailEditorIntegration;
 use MailPoet\EmailEditor\Integrations\MailPoet\Blocks\BlockTypesController;
 use MailPoet\EmailEditor\Integrations\MailPoet\EmailEditor as MailpoetEmailEditorIntegration;
@@ -120,7 +120,7 @@ class Initializer {
   /** @var DaemonActionSchedulerRunner */
   private $actionSchedulerRunner;
 
-  /** @var EmailEditor */
+  /** @var Email_Editor */
   private $emailEditor;
 
   /** @var MailpoetEmailEditorIntegration */
@@ -171,7 +171,7 @@ class Initializer {
     WooCommerceIntegration $woocommerceIntegration,
     PersonalDataExporters $personalDataExporters,
     DaemonActionSchedulerRunner $actionSchedulerRunner,
-    EmailEditor $emailEditor,
+    Email_Editor $emailEditor,
     BlockTypesController $blockTypesController,
     MailpoetEmailEditorIntegration $mailpoetEmailEditorIntegration,
     CoreEmailEditorIntegration $coreEmailEditorIntegration,
diff --git a/mailpoet/lib/DI/ContainerConfigurator.php b/mailpoet/lib/DI/ContainerConfigurator.php
index 28e7cdc548..d6ff04ec69 100644
--- a/mailpoet/lib/DI/ContainerConfigurator.php
+++ b/mailpoet/lib/DI/ContainerConfigurator.php
@@ -337,27 +337,27 @@ class ContainerConfigurator implements IContainerConfigurator {
     $container->autowire(\MailPoet\CustomFields\ApiDataSanitizer::class);
     $container->autowire(\MailPoet\CustomFields\CustomFieldsRepository::class)->setPublic(true);
     // Email Editor
-    $container->autowire(\MailPoet\EmailEditor\Utils\CdnAssetUrl::class)
+    $container->autowire(\MailPoet\EmailEditor\Utils\Cdn_Asset_Url::class)
       ->setPublic(true)
       ->setFactory([__CLASS__, 'getEmailEditorCdnAssetsUrl']);
-    $container->autowire(\MailPoet\EmailEditor\Engine\EmailEditor::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\EmailApiController::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\SettingsController::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\ThemeController::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\HighlightingPostprocessor::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\VariablesPostprocessor::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\BlocksWidthPreprocessor::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\CleanupPreprocessor::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\SpacingPreprocessor::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\TypographyPreprocessor::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Email_Editor::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Email_Api_Controller::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Settings_Controller::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Theme_Controller::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\Highlighting_Postprocessor::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\Variables_Postprocessor::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Blocks_Width_Preprocessor::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Cleanup_Preprocessor::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Spacing_Preprocessor::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Typography_Preprocessor::class)->setPublic(true);
     $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\Renderer::class)->setPublic(true);
     $container->autowire(\MailPoet\EmailEditor\Engine\Templates\Templates::class)->setPublic(true);
     $container->autowire(\MailPoet\EmailEditor\Engine\Templates\Utils::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\Templates\TemplatePreview::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Templates\Template_Preview::class)->setPublic(true);
     $container->autowire(\MailPoet\EmailEditor\Engine\Patterns\Patterns::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\ContentRenderer::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\BlocksRegistry::class)->setPublic(true);
-    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\ProcessManager::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Content_Renderer::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Blocks_Registry::class)->setPublic(true);
+    $container->autowire(\MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Process_Manager::class)->setPublic(true);
     $container->autowire(\MailPoet\EmailEditor\Integrations\Core\Initializer::class)->setPublic(true);
     $container->autowire(\MailPoet\EmailEditor\Integrations\MailPoet\Cli::class)->setPublic(true);
     $container->autowire(\MailPoet\EmailEditor\Integrations\MailPoet\EmailEditor::class)->setPublic(true);
@@ -689,7 +689,7 @@ class ContainerConfigurator implements IContainerConfigurator {
     return new \MailPoet\Util\CdnAssetUrl((string)Env::$baseUrl);
   }
 
-  public static function getEmailEditorCdnAssetsUrl(): \MailPoet\EmailEditor\Utils\CdnAssetUrl {
-    return new \MailPoet\EmailEditor\Utils\CdnAssetUrl((string)Env::$baseUrl);
+  public static function getEmailEditorCdnAssetsUrl(): \MailPoet\EmailEditor\Utils\Cdn_Asset_Url {
+    return new \MailPoet\EmailEditor\Utils\Cdn_Asset_Url((string)Env::$baseUrl);
   }
 }
diff --git a/mailpoet/tests/integration/EmailEditor/Integrations/MailPoet/EmailEditorTest.php b/mailpoet/tests/integration/EmailEditor/Integrations/MailPoet/EmailEditorTest.php
index 235b347738..812b29d5fc 100644
--- a/mailpoet/tests/integration/EmailEditor/Integrations/MailPoet/EmailEditorTest.php
+++ b/mailpoet/tests/integration/EmailEditor/Integrations/MailPoet/EmailEditorTest.php
@@ -21,7 +21,7 @@ class EmailEditorTest extends \MailPoetTest {
 
   public function testItRegistersMailPoetEmailPostType() {
     $this->emailEditor->initialize();
-    $this->diContainer->get(\MailPoet\EmailEditor\Engine\EmailEditor::class)->initialize();
+    $this->diContainer->get(\MailPoet\EmailEditor\Engine\Email_Editor::class)->initialize();
     $postTypes = get_post_types();
     $this->assertArrayHasKey('mailpoet_email', $postTypes);
   }
diff --git a/packages/php/email-editor/composer.json b/packages/php/email-editor/composer.json
index 1c08067bd1..24b1b13f33 100644
--- a/packages/php/email-editor/composer.json
+++ b/packages/php/email-editor/composer.json
@@ -3,14 +3,14 @@
   "description": "Email editor based on WordPress Gutenberg package.",
   "type": "library",
   "autoload": {
-    "psr-4": {
-      "MailPoet\\EmailEditor\\": "src/"
-    }
+    "classmap": [
+      "src/"
+    ]
   },
   "autoload-dev": {
-    "psr-4": {
-      "MailPoet\\EmailEditor\\": "tests/unit/"
-    }
+    "classmap": [
+      "tests/unit/"
+    ]
   },
   "require": {
     "php": ">=7.4"
@@ -28,6 +28,7 @@
   },
   "scripts": {
     "unit-test": "vendor/bin/codecept run unit",
-    "integration-test": "cd ../../../tests_env/docker && COMPOSE_HTTP_TIMEOUT=200 docker compose run -e SKIP_DEPS=1 -e SKIP_PLUGINS=1 -e PACKAGE_NAME=email-editor codeception_integration"
+    "integration-test": "cd ../../../tests_env/docker && COMPOSE_HTTP_TIMEOUT=200 docker compose run -e SKIP_DEPS=1 -e SKIP_PLUGINS=1 -e PACKAGE_NAME=email-editor codeception_integration",
+    "code-style": "../../../mailpoet/tasks/code_sniffer/vendor/bin/phpcs -ps --standard=WordPress src/"
   }
 }
diff --git a/packages/php/email-editor/src/Engine/Patterns/Library/AbstractPattern.php b/packages/php/email-editor/src/Engine/Patterns/Library/class-abstract-pattern.php
similarity index 90%
rename from packages/php/email-editor/src/Engine/Patterns/Library/AbstractPattern.php
rename to packages/php/email-editor/src/Engine/Patterns/Library/class-abstract-pattern.php
index e869abf119..e005a5f04b 100644
--- a/packages/php/email-editor/src/Engine/Patterns/Library/AbstractPattern.php
+++ b/packages/php/email-editor/src/Engine/Patterns/Library/class-abstract-pattern.php
@@ -2,9 +2,9 @@
 
 namespace MailPoet\EmailEditor\Engine\Patterns\Library;
 
-use MailPoet\EmailEditor\Utils\CdnAssetUrl;
+use MailPoet\EmailEditor\Utils\Cdn_Asset_Url;
 
-abstract class AbstractPattern {
+abstract class Abstract_Pattern {
   protected $cdnAssetUrl;
   protected $blockTypes = [];
   protected $templateTypes = [];
@@ -14,7 +14,7 @@ abstract class AbstractPattern {
   protected $viewportWidth = 620;
 
   public function __construct(
-    CdnAssetUrl $cdnAssetUrl
+    Cdn_Asset_Url $cdnAssetUrl
   ) {
     $this->cdnAssetUrl = $cdnAssetUrl;
   }
diff --git a/packages/php/email-editor/src/Engine/Patterns/Library/DefaultContentFull.php b/packages/php/email-editor/src/Engine/Patterns/Library/class-default-content-full.php
similarity index 98%
rename from packages/php/email-editor/src/Engine/Patterns/Library/DefaultContentFull.php
rename to packages/php/email-editor/src/Engine/Patterns/Library/class-default-content-full.php
index fd053d592d..30eada0f28 100644
--- a/packages/php/email-editor/src/Engine/Patterns/Library/DefaultContentFull.php
+++ b/packages/php/email-editor/src/Engine/Patterns/Library/class-default-content-full.php
@@ -2,7 +2,7 @@
 
 namespace MailPoet\EmailEditor\Engine\Patterns\Library;
 
-class DefaultContentFull extends AbstractPattern {
+class Default_Content_Full extends Abstract_Pattern {
   protected $blockTypes = [
     'core/post-content',
   ];
diff --git a/packages/php/email-editor/src/Engine/Patterns/Library/DefaultContent.php b/packages/php/email-editor/src/Engine/Patterns/Library/class-default-content.php
similarity index 95%
rename from packages/php/email-editor/src/Engine/Patterns/Library/DefaultContent.php
rename to packages/php/email-editor/src/Engine/Patterns/Library/class-default-content.php
index 57f0935bda..78dd0d2433 100644
--- a/packages/php/email-editor/src/Engine/Patterns/Library/DefaultContent.php
+++ b/packages/php/email-editor/src/Engine/Patterns/Library/class-default-content.php
@@ -2,7 +2,7 @@
 
 namespace MailPoet\EmailEditor\Engine\Patterns\Library;
 
-class DefaultContent extends AbstractPattern {
+class Default_Content extends Abstract_Pattern {
   protected $blockTypes = [
     'core/post-content',
   ];
@@ -11,7 +11,7 @@ class DefaultContent extends AbstractPattern {
     'email-template',
   ];
 
-  protected function getContent(): string {
+  protected function getContent(): string
     return '
     <!-- wp:columns {"backgroundColor":"white","style":{"spacing":{"padding":{"top":"var:preset|spacing|20","bottom":"var:preset|spacing|20","left":"var:preset|spacing|20","right":"var:preset|spacing|20"}}}} -->
     <div class="wp-block-columns has-white-background-color has-background" style="padding-top:var(--wp--preset--spacing--20);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)"><!-- wp:column -->
diff --git a/packages/php/email-editor/src/Engine/Patterns/Patterns.php b/packages/php/email-editor/src/Engine/Patterns/class-patterns.php
similarity index 76%
rename from packages/php/email-editor/src/Engine/Patterns/Patterns.php
rename to packages/php/email-editor/src/Engine/Patterns/class-patterns.php
index 73f55c0c17..f4d578511d 100644
--- a/packages/php/email-editor/src/Engine/Patterns/Patterns.php
+++ b/packages/php/email-editor/src/Engine/Patterns/class-patterns.php
@@ -2,14 +2,14 @@
 
 namespace MailPoet\EmailEditor\Engine\Patterns;
 
-use MailPoet\EmailEditor\Utils\CdnAssetUrl;
+use MailPoet\EmailEditor\Utils\Cdn_Asset_Url;
 
 class Patterns {
   private $namespace = 'mailpoet';
   protected $cdnAssetUrl;
 
   public function __construct(
-    CdnAssetUrl $cdnAssetUrl
+    Cdn_Asset_Url $cdnAssetUrl
   ) {
     $this->cdnAssetUrl = $cdnAssetUrl;
   }
@@ -30,8 +30,8 @@ class Patterns {
   }
 
   private function registerPatterns() {
-    $this->registerPattern('default', new Library\DefaultContent($this->cdnAssetUrl));
-    $this->registerPattern('default-full', new Library\DefaultContentFull($this->cdnAssetUrl));
+    $this->registerPattern('default', new Library\Default_Content($this->cdnAssetUrl));
+    $this->registerPattern('default-full', new Library\Default_Content_Full($this->cdnAssetUrl));
   }
 
   private function registerPattern($name, $pattern) {
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Layout/FlexLayoutRenderer.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Layout/class-flex-layout-renderer.php
similarity index 95%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Layout/FlexLayoutRenderer.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Layout/class-flex-layout-renderer.php
index 8931ed7e7f..dcd37aec31 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Layout/FlexLayoutRenderer.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Layout/class-flex-layout-renderer.php
@@ -2,13 +2,13 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Layout;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
 /**
  * This class provides functionality to render inner blocks of a block that supports reduced flex layout.
  */
-class FlexLayoutRenderer {
-  public function renderInnerBlocksInLayout(array $parsedBlock, SettingsController $settingsController): string {
+class Flex_Layout_Renderer {
+  public function renderInnerBlocksInLayout(array $parsedBlock, Settings_Controller $settingsController): string {
     $themeStyles = $settingsController->getEmailStyles();
     $flexGap = $themeStyles['spacing']['blockGap'] ?? '0px';
     $flexGapNumber = $settingsController->parseNumberFromStringWithPixels($flexGap);
@@ -45,7 +45,7 @@ class FlexLayoutRenderer {
     return $outputHtml;
   }
 
-  private function computeWidthsForFlexLayout(array $parsedBlock, SettingsController $settingsController, float $flexGap): array {
+  private function computeWidthsForFlexLayout(array $parsedBlock, Settings_Controller $settingsController, float $flexGap): array {
     // When there is no parent width we can't compute widths so auto width will be used
     if (!isset($parsedBlock['email_attrs']['width'])) {
       return $parsedBlock['innerBlocks'] ?? [];
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/HighlightingPostprocessor.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/class-highlighting-postprocessor.php
similarity index 87%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/HighlightingPostprocessor.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/class-highlighting-postprocessor.php
index 5c2655aa65..8254477ef0 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/HighlightingPostprocessor.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/class-highlighting-postprocessor.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors;
 /**
  * This postprocessor replaces <mark> tags with <span> tags because mark tags are not supported across all email clients
  */
-class HighlightingPostprocessor implements Postprocessor {
+class Highlighting_Postprocessor implements Postprocessor {
   public function postprocess(string $html): string {
     return str_replace(
       ['<mark', '</mark>'],
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/VariablesPostprocessor.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/class-variables-postprocessor.php
similarity index 89%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/VariablesPostprocessor.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/class-variables-postprocessor.php
index 404beb4ae8..f4d869658b 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/VariablesPostprocessor.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/class-variables-postprocessor.php
@@ -2,18 +2,18 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors;
 
-use MailPoet\EmailEditor\Engine\ThemeController;
+use MailPoet\EmailEditor\Engine\Theme_Controller;
 
 /**
  * In some case the blocks HTML contains CSS variables.
  * For example when spacing is set from a preset the inline styles contain var(--wp--preset--spacing--10), var(--wp--preset--spacing--20) etc.
  * This postprocessor uses variables from theme.json and replaces the CSS variables with their values in final email HTML.
  */
-class VariablesPostprocessor implements Postprocessor {
-  private ThemeController $themeController;
+class Variables_Postprocessor implements Postprocessor {
+  private Theme_Controller $themeController;
 
   public function __construct(
-    ThemeController $themeController
+    Theme_Controller $themeController
   ) {
     $this->themeController = $themeController;
   }
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/Postprocessor.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/interface-postprocessor.php
similarity index 100%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/Postprocessor.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Postprocessors/interface-postprocessor.php
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/BlocksWidthPreprocessor.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-blocks-width-preprocessor.php
similarity index 99%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/BlocksWidthPreprocessor.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-blocks-width-preprocessor.php
index 158b686ef6..d794abb73f 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/BlocksWidthPreprocessor.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-blocks-width-preprocessor.php
@@ -6,7 +6,7 @@ namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors;
  * This class sets the width of the blocks based on the layout width or column count.
  * The final width in pixels is stored in the email_attrs array because we would like to avoid changing the original attributes.
  */
-class BlocksWidthPreprocessor implements Preprocessor {
+class Blocks_Width_Preprocessor implements Preprocessor {
   public function preprocess(array $parsedBlocks, array $layout, array $styles): array {
     foreach ($parsedBlocks as $key => $block) {
       // Layout width is recalculated for each block because full-width blocks don't exclude padding
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/CleanupPreprocessor.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-cleanup-preprocessor.php
similarity index 92%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/CleanupPreprocessor.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-cleanup-preprocessor.php
index 444645c60a..a0225044ec 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/CleanupPreprocessor.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-cleanup-preprocessor.php
@@ -2,7 +2,7 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors;
 
-class CleanupPreprocessor implements Preprocessor {
+class Cleanup_Preprocessor implements Preprocessor {
   public function preprocess(array $parsedBlocks, array $layout, array $styles): array {
     foreach ($parsedBlocks as $key => $block) {
       // https://core.trac.wordpress.org/ticket/45312
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/SpacingPreprocessor.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-spacing-preprocessor.php
similarity index 96%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/SpacingPreprocessor.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-spacing-preprocessor.php
index 4a9d54ef6b..1dea882572 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/SpacingPreprocessor.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-spacing-preprocessor.php
@@ -6,7 +6,7 @@ namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors;
  * This preprocessor is responsible for setting default spacing values for blocks.
  * In the early development phase, we are setting only margin-top for blocks that are not first or last in the columns block.
  */
-class SpacingPreprocessor implements Preprocessor {
+class Spacing_Preprocessor implements Preprocessor {
   public function preprocess(array $parsedBlocks, array $layout, array $styles): array {
     $parsedBlocks = $this->addBlockGaps($parsedBlocks, $styles['spacing']['blockGap'] ?? '', null);
     return $parsedBlocks;
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/TypographyPreprocessor.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-typography-preprocessor.php
similarity index 94%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/TypographyPreprocessor.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-typography-preprocessor.php
index aa12d3d4b3..f46cf723ba 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/TypographyPreprocessor.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/class-typography-preprocessor.php
@@ -2,9 +2,9 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class TypographyPreprocessor implements Preprocessor {
+class Typography_Preprocessor implements Preprocessor {
   /**
    * List of styles that should be copied from parent to children.
    * @var string[]
@@ -15,11 +15,11 @@ class TypographyPreprocessor implements Preprocessor {
     'text-decoration',
   ];
 
-  /** @var SettingsController */
+  /** @var Settings_Controller */
   private $settingsController;
 
   public function __construct(
-    SettingsController $settingsController
+    Settings_Controller $settingsController
   ) {
     $this->settingsController = $settingsController;
   }
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/Preprocessor.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/interface-preprocessor.php
similarity index 100%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/Preprocessor.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/Preprocessors/interface-preprocessor.php
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/BlockRenderer.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-block-renderer.php
similarity index 55%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/BlockRenderer.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-block-renderer.php
index cd7cbfe05c..91a30143ed 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/BlockRenderer.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-block-renderer.php
@@ -2,8 +2,8 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-interface BlockRenderer {
-  public function render(string $blockContent, array $parsedBlock, SettingsController $settingsController): string;
+interface Block_Renderer {
+  public function render(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string;
 }
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/BlocksParser.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-blocks-parser.php
similarity index 89%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/BlocksParser.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-blocks-parser.php
index b9bf3a1957..048f8cb047 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/BlocksParser.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-blocks-parser.php
@@ -4,7 +4,7 @@ namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer;
 
 use WP_Block_Parser;
 
-class BlocksParser extends WP_Block_Parser {
+class Blocks_Parser extends WP_Block_Parser {
   /**
    * List of parsed blocks
    *
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/BlocksRegistry.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-blocks-registry.php
similarity index 81%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/BlocksRegistry.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-blocks-registry.php
index 865351435c..1c65463b82 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/BlocksRegistry.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-blocks-registry.php
@@ -2,14 +2,14 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer;
 
-class BlocksRegistry {
+class Blocks_Registry {
 
-  /** @var BlockRenderer[] */
+  /** @var Block_Renderer[] */
   private $blockRenderersMap = [];
   /** @var BlockRenderer */
   private $fallbackRenderer = null;
 
-  public function addBlockRenderer(string $blockName, BlockRenderer $renderer): void {
+  public function addBlockRenderer(string $blockName, Block_Renderer $renderer): void {
     $this->blockRenderersMap[$blockName] = $renderer;
   }
 
@@ -21,7 +21,7 @@ class BlocksRegistry {
     return isset($this->blockRenderersMap[$blockName]);
   }
 
-  public function getBlockRenderer(string $blockName): ?BlockRenderer {
+  public function getBlockRenderer(string $blockName): ?Block_Renderer {
     return $this->blockRenderersMap[$blockName] ?? null;
   }
 
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/ContentRenderer.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-content-renderer.php
similarity index 91%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/ContentRenderer.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-content-renderer.php
index 04ff622b54..ecbd8b3f4d 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/ContentRenderer.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-content-renderer.php
@@ -2,27 +2,27 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
-use MailPoet\EmailEditor\Engine\ThemeController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
+use MailPoet\EmailEditor\Engine\Theme_Controller;
 use MailPoetVendor\Pelago\Emogrifier\CssInliner;
 use WP_Block_Template;
 use WP_Post;
 
-class ContentRenderer {
-  private BlocksRegistry $blocksRegistry;
-  private ProcessManager $processManager;
-  private SettingsController $settingsController;
-  private ThemeController $themeController;
+class Content_Renderer {
+  private Blocks_Registry $blocksRegistry;
+  private Process_Manager $processManager;
+  private Settings_Controller $settingsController;
+  private Theme_Controller $themeController;
   private $post = null;
   private $template = null;
 
   const CONTENT_STYLES_FILE = 'content.css';
 
   public function __construct(
-    ProcessManager $preprocessManager,
-    BlocksRegistry $blocksRegistry,
-    SettingsController $settingsController,
-    ThemeController $themeController
+    Process_Manager $preprocessManager,
+    Blocks_Registry $blocksRegistry,
+    Settings_Controller $settingsController,
+    Theme_Controller $themeController
   ) {
     $this->processManager = $preprocessManager;
     $this->blocksRegistry = $blocksRegistry;
@@ -50,7 +50,7 @@ class ContentRenderer {
   }
 
   public function blockParser() {
-    return 'MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\BlocksParser';
+    return 'MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Blocks_Parser';
   }
 
   public function preprocessParsedBlocks(array $parsedBlocks): array {
diff --git a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/ProcessManager.php b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-process-manager.php
similarity index 79%
rename from packages/php/email-editor/src/Engine/Renderer/ContentRenderer/ProcessManager.php
rename to packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-process-manager.php
index 5cb443996b..6c0bcc23d1 100644
--- a/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/ProcessManager.php
+++ b/packages/php/email-editor/src/Engine/Renderer/ContentRenderer/class-process-manager.php
@@ -2,16 +2,16 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\HighlightingPostprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\Highlighting_Postprocessor;
 use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\Postprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\VariablesPostprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\BlocksWidthPreprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\CleanupPreprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\Variables_Postprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Blocks_Width_Preprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Cleanup_Preprocessor;
 use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Preprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\SpacingPreprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\TypographyPreprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Spacing_Preprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Typography_Preprocessor;
 
-class ProcessManager {
+class Process_Manager {
   /** @var Preprocessor[] */
   private $preprocessors = [];
 
@@ -19,12 +19,12 @@ class ProcessManager {
   private $postprocessors = [];
 
   public function __construct(
-    CleanupPreprocessor $cleanupPreprocessor,
-    BlocksWidthPreprocessor $blocksWidthPreprocessor,
-    TypographyPreprocessor $typographyPreprocessor,
-    SpacingPreprocessor $spacingPreprocessor,
-    HighlightingPostprocessor $highlightingPostprocessor,
-    VariablesPostprocessor $variablesPostprocessor
+    Cleanup_Preprocessor $cleanupPreprocessor,
+    Blocks_Width_Preprocessor $blocksWidthPreprocessor,
+    Typography_Preprocessor $typographyPreprocessor,
+    Spacing_Preprocessor $spacingPreprocessor,
+    Highlighting_Postprocessor $highlightingPostprocessor,
+    Variables_Postprocessor $variablesPostprocessor
   ) {
     $this->registerPreprocessor($cleanupPreprocessor);
     $this->registerPreprocessor($blocksWidthPreprocessor);
diff --git a/packages/php/email-editor/src/Engine/Renderer/Renderer.php b/packages/php/email-editor/src/Engine/Renderer/class-renderer.php
similarity index 94%
rename from packages/php/email-editor/src/Engine/Renderer/Renderer.php
rename to packages/php/email-editor/src/Engine/Renderer/class-renderer.php
index 780433ed8e..10749f9e6c 100644
--- a/packages/php/email-editor/src/Engine/Renderer/Renderer.php
+++ b/packages/php/email-editor/src/Engine/Renderer/class-renderer.php
@@ -2,17 +2,17 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\ContentRenderer;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Content_Renderer;
 use MailPoet\EmailEditor\Engine\Templates\Templates;
-use MailPoet\EmailEditor\Engine\ThemeController;
+use MailPoet\EmailEditor\Engine\Theme_Controller;
 use MailPoetVendor\Html2Text\Html2Text;
 use MailPoetVendor\Pelago\Emogrifier\CssInliner;
 use WP_Style_Engine;
 use WP_Theme_JSON;
 
 class Renderer {
-  private ThemeController $themeController;
-  private ContentRenderer $contentRenderer;
+  private Theme_Controller $themeController;
+  private Content_Renderer $contentRenderer;
   private Templates $templates;
   /** @var WP_Theme_JSON|null */
   private static $theme = null;
@@ -21,9 +21,9 @@ class Renderer {
   const TEMPLATE_STYLES_FILE = 'template-canvas.css';
 
   public function __construct(
-    ContentRenderer $contentRenderer,
-    Templates $templates,
-    ThemeController $themeController
+    Content_Renderer $contentRenderer,
+    Templates        $templates,
+    Theme_Controller  $themeController
   ) {
     $this->contentRenderer = $contentRenderer;
     $this->templates = $templates;
diff --git a/packages/php/email-editor/src/Engine/Renderer/readme.md b/packages/php/email-editor/src/Engine/Renderer/readme.md
index bbf9db1046..fffd93410f 100644
--- a/packages/php/email-editor/src/Engine/Renderer/readme.md
+++ b/packages/php/email-editor/src/Engine/Renderer/readme.md
@@ -13,10 +13,10 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
 class Heading extends AbstractBlockRenderer {
-  protected function renderContent($blockContent, array $parsedBlock, SettingsController $settingsController): string {
+  protected function renderContent($blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     return $blockContent;
   }
 }
@@ -28,11 +28,11 @@ class Heading extends AbstractBlockRenderer {
 ```php
 <?php
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\BlocksRegistry;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Blocks_Registry;
 
 add_action('mailpoet_blocks_renderer_initialized', 'register_my_block_email_renderer');
 
-function register_my_block_email_renderer(BlocksRegistry $blocksRegistry): void {
+function register_my_block_email_renderer(Blocks_Registry $blocksRegistry): void {
   $blocksRegistry->addBlockRenderer('core/heading', new Renderer\Blocks\Heading());
 }
 ```
diff --git a/packages/php/email-editor/src/Engine/Templates/TemplatePreview.php b/packages/php/email-editor/src/Engine/Templates/class-template-preview.php
similarity index 83%
rename from packages/php/email-editor/src/Engine/Templates/TemplatePreview.php
rename to packages/php/email-editor/src/Engine/Templates/class-template-preview.php
index 1d69cb67ed..37858df1ee 100644
--- a/packages/php/email-editor/src/Engine/Templates/TemplatePreview.php
+++ b/packages/php/email-editor/src/Engine/Templates/class-template-preview.php
@@ -2,19 +2,19 @@
 
 namespace MailPoet\EmailEditor\Engine\Templates;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
-use MailPoet\EmailEditor\Engine\ThemeController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
+use MailPoet\EmailEditor\Engine\Theme_Controller;
 use MailPoet\EmailEditor\Validator\Builder;
 use WP_Theme_JSON;
 
-class TemplatePreview {
-  private ThemeController $themeController;
-  private SettingsController $settingsController;
+class Template_Preview {
+  private Theme_Controller $themeController;
+  private Settings_Controller $settingsController;
   private Templates $templates;
 
   public function __construct(
-    ThemeController $themeController,
-    SettingsController $settingsController,
+    Theme_Controller $themeController,
+    Settings_Controller $settingsController,
     Templates $templates
   ) {
     $this->themeController = $themeController;
diff --git a/packages/php/email-editor/src/Engine/Templates/Templates.php b/packages/php/email-editor/src/Engine/Templates/class-templates.php
similarity index 98%
rename from packages/php/email-editor/src/Engine/Templates/Templates.php
rename to packages/php/email-editor/src/Engine/Templates/class-templates.php
index ddd34b4afd..baa1b56fb3 100644
--- a/packages/php/email-editor/src/Engine/Templates/Templates.php
+++ b/packages/php/email-editor/src/Engine/Templates/class-templates.php
@@ -2,7 +2,7 @@
 
 namespace MailPoet\EmailEditor\Engine\Templates;
 
-use MailPoet\EmailEditor\Engine\EmailStylesSchema;
+use MailPoet\EmailEditor\Engine\Email_Styles_Schema;
 use WP_Block_Template;
 
 // phpcs:disable Squiz.NamingConventions.ValidVariableName.MemberNotCamelCaps
@@ -187,7 +187,7 @@ class Templates {
       self::MAILPOET_EMAIL_META_THEME_TYPE,
       [
         'show_in_rest' => [
-          'schema' => (new EmailStylesSchema())->getSchema(),
+          'schema' => (new Email_Styles_Schema())->getSchema(),
         ],
         'single' => true,
         'type' => 'object',
@@ -204,7 +204,7 @@ class Templates {
       'update_callback' => function($value, $template) {
         return update_post_meta($template->wp_id, self::MAILPOET_EMAIL_META_THEME_TYPE, $value);
       },
-      'schema' => (new EmailStylesSchema())->getSchema(),
+      'schema' => (new Email_Styles_Schema())->getSchema(),
       ]
     );
   }
diff --git a/packages/php/email-editor/src/Engine/Templates/Utils.php b/packages/php/email-editor/src/Engine/Templates/class-utils.php
similarity index 100%
rename from packages/php/email-editor/src/Engine/Templates/Utils.php
rename to packages/php/email-editor/src/Engine/Templates/class-utils.php
diff --git a/packages/php/email-editor/src/Engine/EmailApiController.php b/packages/php/email-editor/src/Engine/class-email-api-controller.php
similarity index 95%
rename from packages/php/email-editor/src/Engine/EmailApiController.php
rename to packages/php/email-editor/src/Engine/class-email-api-controller.php
index 33d326211b..de3b26d27d 100644
--- a/packages/php/email-editor/src/Engine/EmailApiController.php
+++ b/packages/php/email-editor/src/Engine/class-email-api-controller.php
@@ -4,7 +4,7 @@ namespace MailPoet\EmailEditor\Engine;
 
 use MailPoet\EmailEditor\Validator\Builder;
 
-class EmailApiController {
+class Email_Api_Controller {
   /**
    * @return array - Email specific data such styles.
    */
diff --git a/packages/php/email-editor/src/Engine/EmailEditor.php b/packages/php/email-editor/src/Engine/class-email-editor.php
similarity index 87%
rename from packages/php/email-editor/src/Engine/EmailEditor.php
rename to packages/php/email-editor/src/Engine/class-email-editor.php
index eb4b3eeb33..07255951f9 100644
--- a/packages/php/email-editor/src/Engine/EmailEditor.php
+++ b/packages/php/email-editor/src/Engine/class-email-editor.php
@@ -3,7 +3,7 @@
 namespace MailPoet\EmailEditor\Engine;
 
 use MailPoet\EmailEditor\Engine\Patterns\Patterns;
-use MailPoet\EmailEditor\Engine\Templates\TemplatePreview;
+use MailPoet\EmailEditor\Engine\Templates\Template_Preview;
 use MailPoet\EmailEditor\Engine\Templates\Templates;
 use WP_Post;
 use WP_Theme_JSON;
@@ -12,21 +12,21 @@ use WP_Theme_JSON;
  * @phpstan-type EmailPostType array{name: string, args: array, meta: array{key: string, args: array}[]}
  * See register_post_type for details about EmailPostType args.
  */
-class EmailEditor {
+class Email_Editor {
   public const MAILPOET_EMAIL_META_THEME_TYPE = 'mailpoet_email_theme';
 
-  private EmailApiController $emailApiController;
+  private Email_Api_Controller $emailApiController;
   private Templates $templates;
-  private TemplatePreview $templatePreview;
+  private Template_Preview $templatePreview;
   private Patterns $patterns;
-  private SettingsController $settingsController;
+  private Settings_Controller $settingsController;
 
   public function __construct(
-    EmailApiController $emailApiController,
-    Templates $templates,
-    TemplatePreview $templatePreview,
-    Patterns $patterns,
-    SettingsController $settingsController
+    Email_Api_Controller $emailApiController,
+    Templates            $templates,
+    Template_Preview      $templatePreview,
+    Patterns             $patterns,
+    Settings_Controller   $settingsController
   ) {
     $this->emailApiController = $emailApiController;
     $this->templates = $templates;
@@ -115,11 +115,11 @@ class EmailEditor {
   }
 
   public function getEmailThemeDataSchema(): array {
-    return (new EmailStylesSchema())->getSchema();
+    return (new Email_Styles_Schema())->getSchema();
   }
 
   public function extendEmailThemeStyles(WP_Theme_JSON $theme, WP_Post $post): WP_Theme_JSON {
-    $emailTheme = get_post_meta($post->ID, EmailEditor::MAILPOET_EMAIL_META_THEME_TYPE, true);
+    $emailTheme = get_post_meta($post->ID, Email_Editor::MAILPOET_EMAIL_META_THEME_TYPE, true);
     if ($emailTheme && is_array($emailTheme)) {
       $theme->merge(new WP_Theme_JSON($emailTheme));
     }
diff --git a/packages/php/email-editor/src/Engine/EmailStylesSchema.php b/packages/php/email-editor/src/Engine/class-email-styles-schema.php
similarity index 98%
rename from packages/php/email-editor/src/Engine/EmailStylesSchema.php
rename to packages/php/email-editor/src/Engine/class-email-styles-schema.php
index 84ecea0d82..3382770e28 100644
--- a/packages/php/email-editor/src/Engine/EmailStylesSchema.php
+++ b/packages/php/email-editor/src/Engine/class-email-styles-schema.php
@@ -4,7 +4,7 @@ namespace MailPoet\EmailEditor\Engine;
 
 use MailPoet\EmailEditor\Validator\Builder;
 
-class EmailStylesSchema {
+class Email_Styles_Schema {
   public function getSchema(): array {
     $typographyProps = Builder::object([
       'fontFamily' => Builder::string()->nullable(),
diff --git a/packages/php/email-editor/src/Engine/SettingsController.php b/packages/php/email-editor/src/Engine/class-settings-controller.php
similarity index 96%
rename from packages/php/email-editor/src/Engine/SettingsController.php
rename to packages/php/email-editor/src/Engine/class-settings-controller.php
index 8ab12c4518..4c2be2ef87 100644
--- a/packages/php/email-editor/src/Engine/SettingsController.php
+++ b/packages/php/email-editor/src/Engine/class-settings-controller.php
@@ -2,7 +2,7 @@
 
 namespace MailPoet\EmailEditor\Engine;
 
-class SettingsController {
+class Settings_Controller {
 
   const ALLOWED_BLOCK_TYPES = [
     'core/button',
@@ -22,15 +22,15 @@ class SettingsController {
     'enableCustomUnits' => ['px', '%'],
   ];
 
-  private ThemeController $themeController;
+  private Theme_Controller $themeController;
 
   private array $iframeAssets = [];
 
   /**
-   * @param ThemeController $themeController
+   * @param Theme_Controller $themeController
    */
   public function __construct(
-    ThemeController $themeController
+    Theme_Controller $themeController
   ) {
     $this->themeController = $themeController;
   }
diff --git a/packages/php/email-editor/src/Engine/ThemeController.php b/packages/php/email-editor/src/Engine/class-theme-controller.php
similarity index 99%
rename from packages/php/email-editor/src/Engine/ThemeController.php
rename to packages/php/email-editor/src/Engine/class-theme-controller.php
index 19600d688a..c51ed422d5 100644
--- a/packages/php/email-editor/src/Engine/ThemeController.php
+++ b/packages/php/email-editor/src/Engine/class-theme-controller.php
@@ -10,7 +10,7 @@ use WP_Theme_JSON_Resolver;
  * E-mail editor works with own theme.json which defines settings for the editor and styles for the e-mail.
  * This class is responsible for accessing data defined by the theme.json.
  */
-class ThemeController {
+class Theme_Controller {
   private WP_Theme_JSON $coreTheme;
   private WP_Theme_JSON $baseTheme;
 
diff --git a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/AbstractBlockRenderer.php b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-abstract-block-renderer.php
similarity index 87%
rename from packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/AbstractBlockRenderer.php
rename to packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-abstract-block-renderer.php
index 1108eb44a0..2c4cd6ee97 100644
--- a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/AbstractBlockRenderer.php
+++ b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-abstract-block-renderer.php
@@ -2,14 +2,14 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\BlockRenderer;
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Block_Renderer;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 use WP_Style_Engine;
 
 /**
  * Shared functionality for block renderers.
  */
-abstract class AbstractBlockRenderer implements BlockRenderer {
+abstract class Abstract_Block_Renderer implements Block_Renderer {
   /**
    * Wrapper for wp_style_engine_get_styles which ensures all values are returned.
    *
@@ -54,12 +54,12 @@ abstract class AbstractBlockRenderer implements BlockRenderer {
     );
   }
 
-  public function render(string $blockContent, array $parsedBlock, SettingsController $settingsController): string {
+  public function render(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     return $this->addSpacer(
       $this->renderContent($blockContent, $parsedBlock, $settingsController),
       $parsedBlock['email_attrs'] ?? []
     );
   }
 
-  abstract protected function renderContent(string $blockContent, array $parsedBlock, SettingsController $settingsController): string;
+  abstract protected function renderContent(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string;
 }
diff --git a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Button.php b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-button.php
similarity index 90%
rename from packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Button.php
rename to packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-button.php
index 919ee6f16e..ead1a149fd 100644
--- a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Button.php
+++ b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-button.php
@@ -2,15 +2,15 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
-use MailPoet\EmailEditor\Integrations\Utils\DomDocumentHelper;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
+use MailPoet\EmailEditor\Integrations\Utils\Dom_Document_Helper;
 
 /**
  * Renders a button block.
  * @see https://www.activecampaign.com/blog/email-buttons
  * @see https://documentation.mjml.io/#mj-button
  */
-class Button extends AbstractBlockRenderer {
+class Button extends Abstract_Block_Renderer {
   private function getWrapperStyles(array $blockStyles) {
     $properties = ['border', 'color', 'typography', 'spacing'];
     $styles = $this->getStylesFromBlock(array_intersect_key($blockStyles, array_flip($properties)));
@@ -33,16 +33,16 @@ class Button extends AbstractBlockRenderer {
     ];
   }
 
-  public function render(string $blockContent, array $parsedBlock, SettingsController $settingsController): string {
+  public function render(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     return $this->renderContent($blockContent, $parsedBlock, $settingsController);
   }
 
-  protected function renderContent($blockContent, array $parsedBlock, SettingsController $settingsController): string {
+  protected function renderContent($blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     if (empty($parsedBlock['innerHTML'])) {
       return '';
     }
 
-    $domHelper = new DomDocumentHelper($parsedBlock['innerHTML']);
+    $domHelper = new Dom_Document_Helper($parsedBlock['innerHTML']);
     $blockClassname = $domHelper->getAttributeValueByTagName('div', 'class') ?? '';
     $buttonLink = $domHelper->findElement('a');
 
diff --git a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Buttons.php b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-buttons.php
similarity index 76%
rename from packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Buttons.php
rename to packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-buttons.php
index d90e8474a3..f37ab9efd0 100644
--- a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Buttons.php
+++ b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-buttons.php
@@ -2,20 +2,20 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Layout\FlexLayoutRenderer;
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Layout\Flex_Layout_Renderer;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class Buttons extends AbstractBlockRenderer {
-  /** @var FlexLayoutRenderer */
+class Buttons extends Abstract_Block_Renderer {
+  /** @var Flex_Layout_Renderer */
   private $flexLayoutRenderer;
 
   public function __construct(
-    FlexLayoutRenderer $flexLayoutRenderer
+    Flex_Layout_Renderer $flexLayoutRenderer
   ) {
     $this->flexLayoutRenderer = $flexLayoutRenderer;
   }
 
-  protected function renderContent($blockContent, array $parsedBlock, SettingsController $settingsController): string {
+  protected function renderContent($blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     // Ignore font size set on the buttons block
     // We rely on TypographyPreprocessor to set the font size on the buttons
     // Rendering font size on the wrapper causes unwanted whitespace below the buttons
diff --git a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Column.php b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-column.php
similarity index 87%
rename from packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Column.php
rename to packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-column.php
index 1626ee91f2..a0f694417c 100644
--- a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Column.php
+++ b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-column.php
@@ -2,12 +2,11 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
-use MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks\AbstractBlockRenderer;
-use MailPoet\EmailEditor\Integrations\Utils\DomDocumentHelper;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
+use MailPoet\EmailEditor\Integrations\Utils\Dom_Document_Helper;
 use WP_Style_Engine;
 
-class Column extends AbstractBlockRenderer {
+class Column extends Abstract_Block_Renderer {
   /**
    * Override this method to disable spacing (block gap) for columns.
    * Spacing is applied on wrapping columns block. Columns are rendered side by side so no spacer is needed.
@@ -16,7 +15,7 @@ class Column extends AbstractBlockRenderer {
     return $content;
   }
 
-  protected function renderContent(string $blockContent, array $parsedBlock, SettingsController $settingsController): string {
+  protected function renderContent(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     $content = '';
     foreach ($parsedBlock['innerBlocks'] ?? [] as $block) {
       $content .= render_block($block);
@@ -32,8 +31,8 @@ class Column extends AbstractBlockRenderer {
   /**
    * Based on MJML <mj-column>
    */
-  private function getBlockWrapper(string $blockContent, array $parsedBlock, SettingsController $settingsController): string {
-    $originalWrapperClassname = (new DomDocumentHelper($blockContent))->getAttributeValueByTagName('div', 'class') ?? '';
+  private function getBlockWrapper(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
+    $originalWrapperClassname = (new Dom_Document_Helper($blockContent))->getAttributeValueByTagName('div', 'class') ?? '';
     $block_attributes = wp_parse_args($parsedBlock['attrs'] ?? [], [
       'verticalAlignment' => 'stretch',
       'width' => $settingsController->getLayoutWidthWithoutPadding(),
diff --git a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Columns.php b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-columns.php
similarity index 85%
rename from packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Columns.php
rename to packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-columns.php
index 6f2666a4f7..d009194b5c 100644
--- a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Columns.php
+++ b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-columns.php
@@ -2,13 +2,13 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
-use MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks\AbstractBlockRenderer;
-use MailPoet\EmailEditor\Integrations\Utils\DomDocumentHelper;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
+use MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks\Abstract_Block_Renderer;
+use MailPoet\EmailEditor\Integrations\Utils\Dom_Document_Helper;
 use WP_Style_Engine;
 
-class Columns extends AbstractBlockRenderer {
-  protected function renderContent(string $blockContent, array $parsedBlock, SettingsController $settingsController): string {
+class Columns extends Abstract_Block_Renderer {
+  protected function renderContent(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     $content = '';
     foreach ($parsedBlock['innerBlocks'] ?? [] as $block) {
       $content .= render_block($block);
@@ -24,8 +24,8 @@ class Columns extends AbstractBlockRenderer {
   /**
    * Based on MJML <mj-section>
    */
-  private function getBlockWrapper(string $blockContent, array $parsedBlock, SettingsController $settingsController): string {
-    $originalWrapperClassname = (new DomDocumentHelper($blockContent))->getAttributeValueByTagName('div', 'class') ?? '';
+  private function getBlockWrapper(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
+    $originalWrapperClassname = (new Dom_Document_Helper($blockContent))->getAttributeValueByTagName('div', 'class') ?? '';
     $block_attributes = wp_parse_args($parsedBlock['attrs'] ?? [], [
       'align' => null,
       'width' => $settingsController->getLayoutWidthWithoutPadding(),
diff --git a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Fallback.php b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-fallback.php
similarity index 78%
rename from packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Fallback.php
rename to packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-fallback.php
index 8abf6eb072..ea8447dfeb 100644
--- a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Fallback.php
+++ b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-fallback.php
@@ -2,7 +2,7 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
 /**
  * Fallback block renderer.
@@ -13,8 +13,8 @@ use MailPoet\EmailEditor\Engine\SettingsController;
  *
  * We need to find a better abstraction/architecture for this.
  */
-class Fallback extends AbstractBlockRenderer {
-  protected function renderContent($blockContent, array $parsedBlock, SettingsController $settingsController): string {
+class Fallback extends Abstract_Block_Renderer {
+  protected function renderContent($blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     return $blockContent;
   }
 }
diff --git a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Group.php b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-group.php
similarity index 86%
rename from packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Group.php
rename to packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-group.php
index fe1cdb66ae..7d33b2021a 100644
--- a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Group.php
+++ b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-group.php
@@ -2,13 +2,13 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
-use MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks\AbstractBlockRenderer;
-use MailPoet\EmailEditor\Integrations\Utils\DomDocumentHelper;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
+use MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks\Abstract_Block_Renderer;
+use MailPoet\EmailEditor\Integrations\Utils\Dom_Document_Helper;
 use WP_Style_Engine;
 
-class Group extends AbstractBlockRenderer {
-  protected function renderContent(string $blockContent, array $parsedBlock, SettingsController $settingsController): string {
+class Group extends Abstract_Block_Renderer {
+  protected function renderContent(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     $content = '';
     $innerBlocks = $parsedBlock['innerBlocks'] ?? [];
 
@@ -23,8 +23,8 @@ class Group extends AbstractBlockRenderer {
     );
   }
 
-  private function getBlockWrapper(string $blockContent, array $parsedBlock, SettingsController $settingsController): string {
-    $originalClassname = (new DomDocumentHelper($blockContent))->getAttributeValueByTagName('div', 'class') ?? '';
+  private function getBlockWrapper(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
+    $originalClassname = (new Dom_Document_Helper($blockContent))->getAttributeValueByTagName('div', 'class') ?? '';
     $blockAttributes = wp_parse_args($parsedBlock['attrs'] ?? [], [
       'style' => [],
       'backgroundColor' => '',
diff --git a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Image.php b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-image.php
similarity index 94%
rename from packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Image.php
rename to packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-image.php
index 02ed9c53a3..aed5b189a8 100644
--- a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Image.php
+++ b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-image.php
@@ -2,11 +2,11 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
-use MailPoet\EmailEditor\Integrations\Utils\DomDocumentHelper;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
+use MailPoet\EmailEditor\Integrations\Utils\Dom_Document_Helper;
 
-class Image extends AbstractBlockRenderer {
-  protected function renderContent($blockContent, array $parsedBlock, SettingsController $settingsController): string {
+class Image extends Abstract_Block_Renderer {
+  protected function renderContent($blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     $parsedHtml = $this->parseBlockContent($blockContent);
 
     if (!$parsedHtml) {
@@ -47,7 +47,7 @@ class Image extends AbstractBlockRenderer {
   /**
    * When the width is not set, it's important to get it for the image to be displayed correctly
    */
-  private function addImageSizeWhenMissing(array $parsedBlock, string $imageUrl, SettingsController $settingsController): array {
+  private function addImageSizeWhenMissing(array $parsedBlock, string $imageUrl, Settings_Controller $settingsController): array {
     if (isset($parsedBlock['attrs']['width'])) {
       return $parsedBlock;
     }
@@ -65,7 +65,6 @@ class Image extends AbstractBlockRenderer {
   }
 
   private function applyImageBorderStyle(string $blockContent, array $parsedBlock, string $class): string {
-
     // Getting individual border properties
     $borderStyles = wp_style_engine_get_styles(['border' => $parsedBlock['attrs']['style']['border'] ?? []]);
     $borderStyles = $borderStyles['declarations'] ?? [];
@@ -91,7 +90,7 @@ class Image extends AbstractBlockRenderer {
   /**
    * Settings width and height attributes for images is important for MS Outlook.
    */
-  private function addImageDimensions($blockContent, array $parsedBlock, SettingsController $settingsController): string {
+  private function addImageDimensions($blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     $html = new \WP_HTML_Tag_Processor($blockContent);
     if ($html->next_tag(['tag_name' => 'img'])) {
       // Getting height from styles and if it's set, we set the height attribute
@@ -117,7 +116,7 @@ class Image extends AbstractBlockRenderer {
    * This method configure the font size of the caption because it's set to 0 for the parent element to avoid unexpected white spaces
    * We try to use font-size passed down from the parent element $parsedBlock['email_attrs']['font-size'], but if it's not set, we use the default font-size from the email theme.
    */
-  private function getCaptionStyles(SettingsController $settingsController, array $parsedBlock): string {
+  private function getCaptionStyles(Settings_Controller $settingsController, array $parsedBlock): string {
     $themeData = $settingsController->getTheme()->get_data();
 
     $styles = [
@@ -131,7 +130,7 @@ class Image extends AbstractBlockRenderer {
   /**
    * Based on MJML <mj-image> but because MJML doesn't support captions, our solution is a bit different
    */
-  private function getBlockWrapper(array $parsedBlock, SettingsController $settingsController, ?string $caption): string {
+  private function getBlockWrapper(array $parsedBlock, Settings_Controller $settingsController, ?string $caption): string {
     $styles = [
       'border-collapse' => 'collapse',
       'border-spacing' => '0px',
@@ -244,7 +243,7 @@ class Image extends AbstractBlockRenderer {
       return null;
     }
 
-    $domHelper = new DomDocumentHelper($blockContent);
+    $domHelper = new Dom_Document_Helper($blockContent);
 
     $figureTag = $domHelper->findElement('figure');
     if (!$figureTag) {
diff --git a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/ListBlock.php b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-list-block.php
similarity index 89%
rename from packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/ListBlock.php
rename to packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-list-block.php
index 347b691817..6bb347585b 100644
--- a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/ListBlock.php
+++ b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-list-block.php
@@ -2,11 +2,11 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
 // We have to avoid using keyword `List`
-class ListBlock extends AbstractBlockRenderer {
-  protected function renderContent(string $blockContent, array $parsedBlock, SettingsController $settingsController): string {
+class List_Block extends Abstract_Block_Renderer {
+  protected function renderContent(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     $html = new \WP_HTML_Tag_Processor($blockContent);
     $tagName = ($parsedBlock['attrs']['ordered'] ?? false) ? 'ol' : 'ul';
     if ($html->next_tag(['tag_name' => $tagName])) {
diff --git a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/ListItem.php b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-list-item.php
similarity index 69%
rename from packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/ListItem.php
rename to packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-list-item.php
index 71d4a88ce6..4b420fa574 100644
--- a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/ListItem.php
+++ b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-list-item.php
@@ -2,9 +2,9 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class ListItem extends AbstractBlockRenderer {
+class List_Item extends Abstract_Block_Renderer {
   /**
    * Override this method to disable spacing (block gap) for list items.
    */
@@ -12,7 +12,7 @@ class ListItem extends AbstractBlockRenderer {
     return $content;
   }
 
-  protected function renderContent($blockContent, array $parsedBlock, SettingsController $settingsController): string {
+  protected function renderContent($blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     return $blockContent;
   }
 }
diff --git a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Text.php b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-text.php
similarity index 96%
rename from packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Text.php
rename to packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-text.php
index 4d30944d6e..71729c728d 100644
--- a/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/Text.php
+++ b/packages/php/email-editor/src/Integrations/Core/Renderer/Blocks/class-text.php
@@ -2,13 +2,13 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
 /**
  * This renderer covers both core/paragraph and core/heading blocks
  */
-class Text extends AbstractBlockRenderer {
-  protected function renderContent(string $blockContent, array $parsedBlock, SettingsController $settingsController): string {
+class Text extends Abstract_Block_Renderer {
+  protected function renderContent(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     // Do not render empty blocks.
     if (empty(trim(strip_tags($blockContent)))) {
       return '';
diff --git a/packages/php/email-editor/src/Integrations/Core/Initializer.php b/packages/php/email-editor/src/Integrations/Core/class-initializer.php
similarity index 88%
rename from packages/php/email-editor/src/Integrations/Core/Initializer.php
rename to packages/php/email-editor/src/Integrations/Core/class-initializer.php
index 343cae2115..56edc741c1 100644
--- a/packages/php/email-editor/src/Integrations/Core/Initializer.php
+++ b/packages/php/email-editor/src/Integrations/Core/class-initializer.php
@@ -2,8 +2,8 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\BlocksRegistry;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Layout\FlexLayoutRenderer;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Blocks_Registry;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Layout\Flex_Layout_Renderer;
 
 class Initializer {
   public function initialize(): void {
@@ -15,15 +15,15 @@ class Initializer {
   /**
    * Register core blocks email renderers when the blocks renderer is initialized.
    */
-  public function registerCoreBlocksRenderers(BlocksRegistry $blocksRegistry): void {
+  public function registerCoreBlocksRenderers(Blocks_Registry $blocksRegistry): void {
     $blocksRegistry->addBlockRenderer('core/paragraph', new Renderer\Blocks\Text());
     $blocksRegistry->addBlockRenderer('core/heading', new Renderer\Blocks\Text());
     $blocksRegistry->addBlockRenderer('core/column', new Renderer\Blocks\Column());
     $blocksRegistry->addBlockRenderer('core/columns', new Renderer\Blocks\Columns());
-    $blocksRegistry->addBlockRenderer('core/list', new Renderer\Blocks\ListBlock());
-    $blocksRegistry->addBlockRenderer('core/list-item', new Renderer\Blocks\ListItem());
+    $blocksRegistry->addBlockRenderer('core/list', new Renderer\Blocks\List_Block());
+    $blocksRegistry->addBlockRenderer('core/list-item', new Renderer\Blocks\List_Item());
     $blocksRegistry->addBlockRenderer('core/image', new Renderer\Blocks\Image());
-    $blocksRegistry->addBlockRenderer('core/buttons', new Renderer\Blocks\Buttons(new FlexLayoutRenderer()));
+    $blocksRegistry->addBlockRenderer('core/buttons', new Renderer\Blocks\Buttons(new Flex_Layout_Renderer()));
     $blocksRegistry->addBlockRenderer('core/button', new Renderer\Blocks\Button());
     $blocksRegistry->addBlockRenderer('core/group', new Renderer\Blocks\Group());
     // Render used for all other blocks
diff --git a/packages/php/email-editor/src/Integrations/Utils/DomDocumentHelper.php b/packages/php/email-editor/src/Integrations/Utils/class-dom-document-helper.php
similarity index 98%
rename from packages/php/email-editor/src/Integrations/Utils/DomDocumentHelper.php
rename to packages/php/email-editor/src/Integrations/Utils/class-dom-document-helper.php
index afcaf35882..9e864d6f62 100644
--- a/packages/php/email-editor/src/Integrations/Utils/DomDocumentHelper.php
+++ b/packages/php/email-editor/src/Integrations/Utils/class-dom-document-helper.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Integrations\Utils;
 /**
  * This class should guarantee that our work with the DOMDocument is unified and safe.
  */
-class DomDocumentHelper {
+class Dom_Document_Helper {
   private \DOMDocument $dom;
 
   public function __construct(
diff --git a/packages/php/email-editor/src/Utils/CdnAssetUrl.php b/packages/php/email-editor/src/Utils/class-cdn-asset-url.php
similarity index 96%
rename from packages/php/email-editor/src/Utils/CdnAssetUrl.php
rename to packages/php/email-editor/src/Utils/class-cdn-asset-url.php
index 52ba3b9087..b2900bec67 100644
--- a/packages/php/email-editor/src/Utils/CdnAssetUrl.php
+++ b/packages/php/email-editor/src/Utils/class-cdn-asset-url.php
@@ -2,7 +2,7 @@
 
 namespace MailPoet\EmailEditor\Utils;
 
-class CdnAssetUrl {
+class Cdn_Asset_Url {
   const CDN_URL = 'https://ps.w.org/mailpoet/';
   /** @var string */
   private $baseUrl;
diff --git a/packages/php/email-editor/src/Validator/Builder.php b/packages/php/email-editor/src/Validator/Builder.php
deleted file mode 100644
index 859b9aaa46..0000000000
--- a/packages/php/email-editor/src/Validator/Builder.php
+++ /dev/null
@@ -1,57 +0,0 @@
-<?php declare(strict_types = 1);
-
-namespace MailPoet\EmailEditor\Validator;
-
-use MailPoet\EmailEditor\Validator\Schema\AnyOfSchema;
-use MailPoet\EmailEditor\Validator\Schema\ArraySchema;
-use MailPoet\EmailEditor\Validator\Schema\BooleanSchema;
-use MailPoet\EmailEditor\Validator\Schema\IntegerSchema;
-use MailPoet\EmailEditor\Validator\Schema\NullSchema;
-use MailPoet\EmailEditor\Validator\Schema\NumberSchema;
-use MailPoet\EmailEditor\Validator\Schema\ObjectSchema;
-use MailPoet\EmailEditor\Validator\Schema\OneOfSchema;
-use MailPoet\EmailEditor\Validator\Schema\StringSchema;
-
-// See: https://developer.wordpress.org/rest-api/extending-the-rest-api/schema/
-class Builder {
-  public static function string(): StringSchema {
-    return new StringSchema();
-  }
-
-  public static function number(): NumberSchema {
-    return new NumberSchema();
-  }
-
-  public static function integer(): IntegerSchema {
-    return new IntegerSchema();
-  }
-
-  public static function boolean(): BooleanSchema {
-    return new BooleanSchema();
-  }
-
-  public static function null(): NullSchema {
-    return new NullSchema();
-  }
-
-  public static function array(Schema $items = null): ArraySchema {
-    $array = new ArraySchema();
-    return $items ? $array->items($items) : $array;
-  }
-
-  /** @param array<string, Schema>|null $properties */
-  public static function object(array $properties = null): ObjectSchema {
-    $object = new ObjectSchema();
-    return $properties === null ? $object : $object->properties($properties);
-  }
-
-  /** @param Schema[] $schemas */
-  public static function oneOf(array $schemas): OneOfSchema {
-    return new OneOfSchema($schemas);
-  }
-
-  /** @param Schema[] $schemas */
-  public static function anyOf(array $schemas): AnyOfSchema {
-    return new AnyOfSchema($schemas);
-  }
-}
diff --git a/packages/php/email-editor/src/Validator/Schema/AnyOfSchema.php b/packages/php/email-editor/src/Validator/Schema/class-any-of-schema.php
similarity index 96%
rename from packages/php/email-editor/src/Validator/Schema/AnyOfSchema.php
rename to packages/php/email-editor/src/Validator/Schema/class-any-of-schema.php
index 9bbf4990e3..823e99d937 100644
--- a/packages/php/email-editor/src/Validator/Schema/AnyOfSchema.php
+++ b/packages/php/email-editor/src/Validator/Schema/class-any-of-schema.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Validator\Schema;
 use MailPoet\EmailEditor\Validator\Schema;
 
 // See: https://developer.wordpress.org/rest-api/extending-the-rest-api/schema/#oneof-and-anyof
-class AnyOfSchema extends Schema {
+class Any_Of_Schema extends Schema {
   protected $schema = [
     'anyOf' => [],
   ];
diff --git a/packages/php/email-editor/src/Validator/Schema/ArraySchema.php b/packages/php/email-editor/src/Validator/Schema/class-array-schema.php
similarity index 95%
rename from packages/php/email-editor/src/Validator/Schema/ArraySchema.php
rename to packages/php/email-editor/src/Validator/Schema/class-array-schema.php
index ba813b25fe..9860d01fb3 100644
--- a/packages/php/email-editor/src/Validator/Schema/ArraySchema.php
+++ b/packages/php/email-editor/src/Validator/Schema/class-array-schema.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Validator\Schema;
 use MailPoet\EmailEditor\Validator\Schema;
 
 // See: https://developer.wordpress.org/rest-api/extending-the-rest-api/schema/#arrays
-class ArraySchema extends Schema {
+class Array_Schema extends Schema {
   protected $schema = [
     'type' => 'array',
   ];
diff --git a/packages/php/email-editor/src/Validator/Schema/BooleanSchema.php b/packages/php/email-editor/src/Validator/Schema/class-boolean-schema.php
similarity index 88%
rename from packages/php/email-editor/src/Validator/Schema/BooleanSchema.php
rename to packages/php/email-editor/src/Validator/Schema/class-boolean-schema.php
index 509607526c..023ea2fcd2 100644
--- a/packages/php/email-editor/src/Validator/Schema/BooleanSchema.php
+++ b/packages/php/email-editor/src/Validator/Schema/class-boolean-schema.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Validator\Schema;
 use MailPoet\EmailEditor\Validator\Schema;
 
 // See: https://developer.wordpress.org/rest-api/extending-the-rest-api/schema/#primitive-types
-class BooleanSchema extends Schema {
+class Boolean_Schema extends Schema {
   protected $schema = [
     'type' => 'boolean',
   ];
diff --git a/packages/php/email-editor/src/Validator/Schema/IntegerSchema.php b/packages/php/email-editor/src/Validator/Schema/class-integer-schema.php
similarity index 96%
rename from packages/php/email-editor/src/Validator/Schema/IntegerSchema.php
rename to packages/php/email-editor/src/Validator/Schema/class-integer-schema.php
index e150e1c6c2..753bd6213d 100644
--- a/packages/php/email-editor/src/Validator/Schema/IntegerSchema.php
+++ b/packages/php/email-editor/src/Validator/Schema/class-integer-schema.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Validator\Schema;
 use MailPoet\EmailEditor\Validator\Schema;
 
 // See: https://developer.wordpress.org/rest-api/extending-the-rest-api/schema/#numbers
-class IntegerSchema extends Schema {
+class Integer_Schema extends Schema {
   protected $schema = [
     'type' => 'integer',
   ];
diff --git a/packages/php/email-editor/src/Validator/Schema/NullSchema.php b/packages/php/email-editor/src/Validator/Schema/class-null-schema.php
similarity index 88%
rename from packages/php/email-editor/src/Validator/Schema/NullSchema.php
rename to packages/php/email-editor/src/Validator/Schema/class-null-schema.php
index 4e23e0471b..329c4d7ff6 100644
--- a/packages/php/email-editor/src/Validator/Schema/NullSchema.php
+++ b/packages/php/email-editor/src/Validator/Schema/class-null-schema.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Validator\Schema;
 use MailPoet\EmailEditor\Validator\Schema;
 
 // See: https://developer.wordpress.org/rest-api/extending-the-rest-api/schema/#primitive-types
-class NullSchema extends Schema {
+class Null_Schema extends Schema {
   protected $schema = [
     'type' => 'null',
   ];
diff --git a/packages/php/email-editor/src/Validator/Schema/NumberSchema.php b/packages/php/email-editor/src/Validator/Schema/class-number-schema.php
similarity index 96%
rename from packages/php/email-editor/src/Validator/Schema/NumberSchema.php
rename to packages/php/email-editor/src/Validator/Schema/class-number-schema.php
index 3249e95078..11dac4c519 100644
--- a/packages/php/email-editor/src/Validator/Schema/NumberSchema.php
+++ b/packages/php/email-editor/src/Validator/Schema/class-number-schema.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Validator\Schema;
 use MailPoet\EmailEditor\Validator\Schema;
 
 // See: https://developer.wordpress.org/rest-api/extending-the-rest-api/schema/#numbers
-class NumberSchema extends Schema {
+class Number_Schema extends Schema {
   protected $schema = [
     'type' => 'number',
   ];
diff --git a/packages/php/email-editor/src/Validator/Schema/ObjectSchema.php b/packages/php/email-editor/src/Validator/Schema/class-object-schema.php
similarity index 97%
rename from packages/php/email-editor/src/Validator/Schema/ObjectSchema.php
rename to packages/php/email-editor/src/Validator/Schema/class-object-schema.php
index ebebebe45b..c8e666f850 100644
--- a/packages/php/email-editor/src/Validator/Schema/ObjectSchema.php
+++ b/packages/php/email-editor/src/Validator/Schema/class-object-schema.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Validator\Schema;
 use MailPoet\EmailEditor\Validator\Schema;
 
 // See: https://developer.wordpress.org/rest-api/extending-the-rest-api/schema/#objects
-class ObjectSchema extends Schema {
+class Object_Schema extends Schema {
   protected $schema = [
     'type' => 'object',
   ];
diff --git a/packages/php/email-editor/src/Validator/Schema/OneOfSchema.php b/packages/php/email-editor/src/Validator/Schema/class-one-of-schema.php
similarity index 96%
rename from packages/php/email-editor/src/Validator/Schema/OneOfSchema.php
rename to packages/php/email-editor/src/Validator/Schema/class-one-of-schema.php
index 36d4737d2d..5d1e540e2e 100644
--- a/packages/php/email-editor/src/Validator/Schema/OneOfSchema.php
+++ b/packages/php/email-editor/src/Validator/Schema/class-one-of-schema.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Validator\Schema;
 use MailPoet\EmailEditor\Validator\Schema;
 
 // See: https://developer.wordpress.org/rest-api/extending-the-rest-api/schema/#oneof-and-anyof
-class OneOfSchema extends Schema {
+class One_Of_Schema extends Schema {
   protected $schema = [
     'oneOf' => [],
   ];
diff --git a/packages/php/email-editor/src/Validator/Schema/StringSchema.php b/packages/php/email-editor/src/Validator/Schema/class-string-schema.php
similarity index 97%
rename from packages/php/email-editor/src/Validator/Schema/StringSchema.php
rename to packages/php/email-editor/src/Validator/Schema/class-string-schema.php
index d002ba5736..b253f770dc 100644
--- a/packages/php/email-editor/src/Validator/Schema/StringSchema.php
+++ b/packages/php/email-editor/src/Validator/Schema/class-string-schema.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Validator\Schema;
 use MailPoet\EmailEditor\Validator\Schema;
 
 // See: https://developer.wordpress.org/rest-api/extending-the-rest-api/schema/#strings
-class StringSchema extends Schema {
+class String_Schema extends Schema {
   protected $schema = [
     'type' => 'string',
   ];
diff --git a/packages/php/email-editor/src/Validator/class-builder.php b/packages/php/email-editor/src/Validator/class-builder.php
new file mode 100644
index 0000000000..0a8ce356ba
--- /dev/null
+++ b/packages/php/email-editor/src/Validator/class-builder.php
@@ -0,0 +1,57 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\EmailEditor\Validator;
+
+use MailPoet\EmailEditor\Validator\Schema\Any_Of_Schema;
+use MailPoet\EmailEditor\Validator\Schema\Array_Schema;
+use MailPoet\EmailEditor\Validator\Schema\Boolean_Schema;
+use MailPoet\EmailEditor\Validator\Schema\Integer_Schema;
+use MailPoet\EmailEditor\Validator\Schema\Null_Schema;
+use MailPoet\EmailEditor\Validator\Schema\Number_Schema;
+use MailPoet\EmailEditor\Validator\Schema\Object_Schema;
+use MailPoet\EmailEditor\Validator\Schema\One_Of_Schema;
+use MailPoet\EmailEditor\Validator\Schema\String_Schema;
+
+// See: https://developer.wordpress.org/rest-api/extending-the-rest-api/schema/
+class Builder {
+  public static function string(): String_Schema {
+    return new String_Schema();
+  }
+
+  public static function number(): Number_Schema {
+    return new Number_Schema();
+  }
+
+  public static function integer(): Integer_Schema {
+    return new Integer_Schema();
+  }
+
+  public static function boolean(): Boolean_Schema {
+    return new Boolean_Schema();
+  }
+
+  public static function null(): Null_Schema {
+    return new Null_Schema();
+  }
+
+  public static function array(Schema $items = null): Array_Schema {
+    $array = new Array_Schema();
+    return $items ? $array->items($items) : $array;
+  }
+
+  /** @param array<string, Schema>|null $properties */
+  public static function object(array $properties = null): Object_Schema {
+    $object = new Object_Schema();
+    return $properties === null ? $object : $object->properties($properties);
+  }
+
+  /** @param Schema[] $schemas */
+  public static function oneOf(array $schemas): One_Of_Schema {
+    return new One_Of_Schema($schemas);
+  }
+
+  /** @param Schema[] $schemas */
+  public static function anyOf(array $schemas): Any_Of_Schema {
+    return new Any_Of_Schema($schemas);
+  }
+}
diff --git a/packages/php/email-editor/src/Validator/Schema.php b/packages/php/email-editor/src/Validator/class-schema.php
similarity index 100%
rename from packages/php/email-editor/src/Validator/Schema.php
rename to packages/php/email-editor/src/Validator/class-schema.php
diff --git a/packages/php/email-editor/src/Validator/ValidationException.php b/packages/php/email-editor/src/Validator/class-validation-exception.php
similarity index 88%
rename from packages/php/email-editor/src/Validator/ValidationException.php
rename to packages/php/email-editor/src/Validator/class-validation-exception.php
index b0b2237a56..72d27df852 100644
--- a/packages/php/email-editor/src/Validator/ValidationException.php
+++ b/packages/php/email-editor/src/Validator/class-validation-exception.php
@@ -5,7 +5,7 @@ namespace MailPoet\EmailEditor\Validator;
 use MailPoet\UnexpectedValueException;
 use WP_Error;
 
-class ValidationException extends UnexpectedValueException {
+class Validation_Exception extends UnexpectedValueException {
   /** @var WP_Error */
   protected $wpError;
 
diff --git a/packages/php/email-editor/src/Validator/Validator.php b/packages/php/email-editor/src/Validator/class-validator.php
similarity index 99%
rename from packages/php/email-editor/src/Validator/Validator.php
rename to packages/php/email-editor/src/Validator/class-validator.php
index b61498b0bf..2c0d601ce6 100644
--- a/packages/php/email-editor/src/Validator/Validator.php
+++ b/packages/php/email-editor/src/Validator/class-validator.php
@@ -39,7 +39,7 @@ class Validator {
   public function validateSchemaArray(array $schema, $value, string $paramName = 'value') {
     $result = $this->validateAndSanitizeValueFromSchema($value, $schema, $paramName);
     if ($result instanceof WP_Error) {
-      throw ValidationException::createFromWpError($result);
+      throw Validation_Exception::createFromWpError($result);
     }
     return $result;
   }
diff --git a/packages/php/email-editor/src/Container.php b/packages/php/email-editor/src/class-container.php
similarity index 100%
rename from packages/php/email-editor/src/Container.php
rename to packages/php/email-editor/src/class-container.php
diff --git a/packages/php/email-editor/tests/_support/UnitTester.php b/packages/php/email-editor/tests/_support/UnitTester.php
index 3a743e27e2..264259b83f 100644
--- a/packages/php/email-editor/tests/_support/UnitTester.php
+++ b/packages/php/email-editor/tests/_support/UnitTester.php
@@ -1,5 +1,6 @@
 <?php
 
+use _generated\UnitTesterActions;
 
 /**
  * Inherited Methods
@@ -18,7 +19,7 @@
 */
 class UnitTester extends \Codeception\Actor
 {
-    use _generated\UnitTesterActions;
+    use UnitTesterActions;
 
     /**
      * Define custom actions here
diff --git a/packages/php/email-editor/tests/integration/Engine/EmailEditorTest.php b/packages/php/email-editor/tests/integration/Engine/Email_Editor_Test.php
similarity index 85%
rename from packages/php/email-editor/tests/integration/Engine/EmailEditorTest.php
rename to packages/php/email-editor/tests/integration/Engine/Email_Editor_Test.php
index 75049698cc..c386342982 100644
--- a/packages/php/email-editor/tests/integration/Engine/EmailEditorTest.php
+++ b/packages/php/email-editor/tests/integration/Engine/Email_Editor_Test.php
@@ -2,8 +2,8 @@
 
 namespace MailPoet\EmailEditor\Engine;
 
-class EmailEditorTest extends \MailPoetTest {
-  /** @var EmailEditor */
+class Email_Editor_Test extends \MailPoetTest {
+  /** @var Email_Editor */
   private $emailEditor;
 
   /** @var callable */
@@ -11,7 +11,7 @@ class EmailEditorTest extends \MailPoetTest {
 
   public function _before() {
     parent::_before();
-    $this->emailEditor = $this->diContainer->get(EmailEditor::class);
+    $this->emailEditor = $this->diContainer->get(Email_Editor::class);
     $this->postRegisterCallback = function ($postTypes) {
       $postTypes[] = [
         'name' => 'custom_email_type',
diff --git a/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/BlocksRegistryTest.php b/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Blocks_Registry_Test.php
similarity index 82%
rename from packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/BlocksRegistryTest.php
rename to packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Blocks_Registry_Test.php
index f93ee25768..671b64eb4b 100644
--- a/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/BlocksRegistryTest.php
+++ b/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Blocks_Registry_Test.php
@@ -4,16 +4,16 @@ namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer;
 
 use MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks\Text;
 
-require_once __DIR__ . '/DummyBlockRenderer.php';
+require_once __DIR__ . '/Dummy_Block_Renderer.php';
 
-class BlocksRegistryTest extends \MailPoetTest {
+class Blocks_Registry_Test extends \MailPoetTest {
 
-  /** @var BlocksRegistry */
+  /** @var Blocks_Registry */
   private $registry;
 
   public function _before() {
     parent::_before();
-    $this->registry = $this->diContainer->get(BlocksRegistry::class);
+    $this->registry = $this->diContainer->get(Blocks_Registry::class);
   }
 
   public function testItReturnsNullForUnknownRenderer() {
diff --git a/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/ContentRendererTest.php b/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Content_Renderer_Test.php
similarity index 82%
rename from packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/ContentRendererTest.php
rename to packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Content_Renderer_Test.php
index 6d42dbea08..f8ed1ce2bc 100644
--- a/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/ContentRendererTest.php
+++ b/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Content_Renderer_Test.php
@@ -2,21 +2,21 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer;
 
-use MailPoet\EmailEditor\Engine\EmailEditor;
+use MailPoet\EmailEditor\Engine\Email_Editor;
 use MailPoet\EmailEditor\Integrations\MailPoet\Blocks\BlockTypesController;
 
-require_once __DIR__ . '/DummyBlockRenderer.php';
+require_once __DIR__ . '/Dummy_Block_Renderer.php';
 
-class ContentRendererTest extends \MailPoetTest {
-  private ContentRenderer $renderer;
+class Content_Renderer_Test extends \MailPoetTest {
+  private Content_Renderer $renderer;
 
   private \WP_Post $emailPost;
 
   public function _before(): void {
     parent::_before();
-    $this->diContainer->get(EmailEditor::class)->initialize();
+    $this->diContainer->get(Email_Editor::class)->initialize();
     $this->diContainer->get(BlockTypesController::class)->initialize();
-    $this->renderer = $this->diContainer->get(ContentRenderer::class);
+    $this->renderer = $this->diContainer->get(Content_Renderer::class);
     $this->emailPost = $this->tester->createPost([
       'post_content' => '<!-- wp:paragraph --><p>Hello!</p><!-- /wp:paragraph -->',
     ]);
diff --git a/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/DummyBlockRenderer.php b/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Dummy_Block_Renderer.php
similarity index 56%
rename from packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/DummyBlockRenderer.php
rename to packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Dummy_Block_Renderer.php
index 34ae8dcbf9..b79ab033a7 100644
--- a/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/DummyBlockRenderer.php
+++ b/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Dummy_Block_Renderer.php
@@ -2,10 +2,10 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer;
 
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class DummyBlockRenderer implements BlockRenderer {
-  public function render(string $blockContent, array $parsedBlock, SettingsController $settingsController): string {
+class Dummy_Block_Renderer implements Block_Renderer {
+  public function render(string $blockContent, array $parsedBlock, Settings_Controller $settingsController): string {
     return $parsedBlock['innerHtml'];
   }
 }
diff --git a/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Layout/FlexLayoutRendererTest.php b/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Layout/Flex_Layout_Renderer_Test.php
similarity index 94%
rename from packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Layout/FlexLayoutRendererTest.php
rename to packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Layout/Flex_Layout_Renderer_Test.php
index 9323b10fc6..1f96c87fcc 100644
--- a/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Layout/FlexLayoutRendererTest.php
+++ b/packages/php/email-editor/tests/integration/Engine/Renderer/ContentRenderer/Layout/Flex_Layout_Renderer_Test.php
@@ -2,23 +2,23 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Layout;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\DummyBlockRenderer;
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Dummy_Block_Renderer;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-require_once __DIR__ . '/../DummyBlockRenderer.php';
+require_once __DIR__ . '/../Dummy_Block_Renderer.php';
 
-class FlexLayoutRendererTest extends \MailPoetTest {
+class Flex_Layout_Renderer_Test extends \MailPoetTest {
 
-  /** @var FlexLayoutRenderer */
+  /** @var Flex_Layout_Renderer */
   private $renderer;
 
-  /** @var SettingsController */
+  /** @var Settings_Controller */
   private $settingsController;
 
   public function _before(): void {
     parent::_before();
-    $this->settingsController = $this->diContainer->get(SettingsController::class);
-    $this->renderer = new FlexLayoutRenderer();
+    $this->settingsController = $this->diContainer->get(Settings_Controller::class);
+    $this->renderer = new Flex_Layout_Renderer();
     register_block_type('dummy/block', []);
     add_filter('render_block', [$this, 'renderDummyBlock'], 10, 2);
   }
@@ -223,7 +223,7 @@ class FlexLayoutRendererTest extends \MailPoetTest {
   }
 
   public function renderDummyBlock($blockContent, $parsedBlock): string {
-    $dummyRenderer = new DummyBlockRenderer();
+    $dummyRenderer = new Dummy_Block_Renderer();
     return $dummyRenderer->render($blockContent, $parsedBlock, $this->settingsController);
   }
 
diff --git a/packages/php/email-editor/tests/integration/Engine/Renderer/RendererTest.php b/packages/php/email-editor/tests/integration/Engine/Renderer/Renderer_Test.php
similarity index 91%
rename from packages/php/email-editor/tests/integration/Engine/Renderer/RendererTest.php
rename to packages/php/email-editor/tests/integration/Engine/Renderer/Renderer_Test.php
index 4cc1f6d061..08869b0e61 100644
--- a/packages/php/email-editor/tests/integration/Engine/Renderer/RendererTest.php
+++ b/packages/php/email-editor/tests/integration/Engine/Renderer/Renderer_Test.php
@@ -2,18 +2,18 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer;
 
-use MailPoet\EmailEditor\Engine\EmailEditor;
-use MailPoet\EmailEditor\Engine\SettingsController;
-use MailPoet\EmailEditor\Engine\ThemeController;
+use MailPoet\EmailEditor\Engine\Email_Editor;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
+use MailPoet\EmailEditor\Engine\Theme_Controller;
 
-class RendererTest extends \MailPoetTest {
+class Renderer_Test extends \MailPoetTest {
   private Renderer $renderer;
 
   private \WP_Post $emailPost;
 
   public function _before(): void {
     parent::_before();
-    $this->diContainer->get(EmailEditor::class)->initialize();
+    $this->diContainer->get(Email_Editor::class)->initialize();
     $this->renderer = $this->diContainer->get(Renderer::class);
     $styles = [
       'spacing' => [
@@ -35,9 +35,9 @@ class RendererTest extends \MailPoetTest {
     $themeJsonMock->method('get_data')->willReturn([
       'styles' => $styles,
     ]);
-    $settingsControllerMock = $this->createMock(SettingsController::class);
+    $settingsControllerMock = $this->createMock(Settings_Controller::class);
     $settingsControllerMock->method('getEmailStyles')->willReturn($styles);
-    $themeControllerMock = $this->createMock(ThemeController::class);
+    $themeControllerMock = $this->createMock(Theme_Controller::class);
     $themeControllerMock->method('getTheme')->willReturn($themeJsonMock);
     $themeControllerMock->method('getStyles')->willReturn($styles);
     $themeControllerMock->method('getLayoutSettings')->willReturn(['contentSize' => '660px']);
diff --git a/packages/php/email-editor/tests/integration/Engine/ThemeControllerTest.php b/packages/php/email-editor/tests/integration/Engine/Theme_Controller_Test.php
similarity index 96%
rename from packages/php/email-editor/tests/integration/Engine/ThemeControllerTest.php
rename to packages/php/email-editor/tests/integration/Engine/Theme_Controller_Test.php
index 5e4855659e..9898299faf 100644
--- a/packages/php/email-editor/tests/integration/Engine/ThemeControllerTest.php
+++ b/packages/php/email-editor/tests/integration/Engine/Theme_Controller_Test.php
@@ -2,12 +2,12 @@
 
 namespace MailPoet\EmailEditor\Engine;
 
-class ThemeControllerTest extends \MailPoetTest {
-  private ThemeController $themeController;
+class Theme_Controller_Test extends \MailPoetTest {
+  private Theme_Controller $themeController;
 
   public function _before() {
     parent::_before();
-    $this->themeController = $this->diContainer->get(ThemeController::class);
+    $this->themeController = $this->diContainer->get(Theme_Controller::class);
   }
 
   public function testItGeneratesCssStylesForRenderer() {
diff --git a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ButtonTest.php b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Button_Test.php
similarity index 96%
rename from packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ButtonTest.php
rename to packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Button_Test.php
index cb4db30625..b3324df214 100644
--- a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ButtonTest.php
+++ b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Button_Test.php
@@ -2,10 +2,10 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\EmailEditor;
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Email_Editor;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class ButtonTest extends \MailPoetTest {
+class Button_Test extends \MailPoetTest {
   /** @var Button */
   private $buttonRenderer;
 
@@ -38,13 +38,13 @@ class ButtonTest extends \MailPoetTest {
     ],
   ];
 
-  /** @var SettingsController */
+  /** @var Settings_Controller */
   private $settingsController;
 
   public function _before(): void {
-    $this->diContainer->get(EmailEditor::class)->initialize();
+    $this->diContainer->get(Email_Editor::class)->initialize();
     $this->buttonRenderer = new Button();
-    $this->settingsController = $this->diContainer->get(SettingsController::class);
+    $this->settingsController = $this->diContainer->get(Settings_Controller::class);
   }
 
   public function testItRendersLink(): void {
diff --git a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ColumnTest.php b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Column_Test.php
similarity index 95%
rename from packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ColumnTest.php
rename to packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Column_Test.php
index ca2b5e71f0..453f2993d5 100644
--- a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ColumnTest.php
+++ b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Column_Test.php
@@ -2,10 +2,10 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\EmailEditor;
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Email_Editor;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class ColumnTest extends \MailPoetTest {
+class Column_Test extends \MailPoetTest {
   /** @var Column */
   private $columnRenderer;
 
@@ -35,13 +35,13 @@ class ColumnTest extends \MailPoetTest {
      ],
   ];
 
-  /** @var SettingsController */
+  /** @var Settings_Controller */
   private $settingsController;
 
   public function _before() {
-    $this->diContainer->get(EmailEditor::class)->initialize();
+    $this->diContainer->get(Email_Editor::class)->initialize();
     $this->columnRenderer = new Column();
-    $this->settingsController = $this->diContainer->get(SettingsController::class);
+    $this->settingsController = $this->diContainer->get(Settings_Controller::class);
   }
 
   public function testItRendersColumnContent() {
diff --git a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ColumnsTest.php b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Columns_Test.php
similarity index 93%
rename from packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ColumnsTest.php
rename to packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Columns_Test.php
index a637e241a2..a390e8885d 100644
--- a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ColumnsTest.php
+++ b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Columns_Test.php
@@ -2,10 +2,10 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\EmailEditor;
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Email_Editor;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class ColumnsTest extends \MailPoetTest {
+class Columns_Test extends \MailPoetTest {
   /** @var Columns */
   private $columnsRenderer;
 
@@ -42,13 +42,13 @@ class ColumnsTest extends \MailPoetTest {
     ],
   ];
 
-  /** @var SettingsController */
+  /** @var Settings_Controller */
   private $settingsController;
 
   public function _before() {
-    $this->diContainer->get(EmailEditor::class)->initialize();
+    $this->diContainer->get(Email_Editor::class)->initialize();
     $this->columnsRenderer = new Columns();
-    $this->settingsController = $this->diContainer->get(SettingsController::class);
+    $this->settingsController = $this->diContainer->get(Settings_Controller::class);
   }
 
   public function testItRendersInnerColumn() {
diff --git a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/HeadingTest.php b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Heading_Test.php
similarity index 91%
rename from packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/HeadingTest.php
rename to packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Heading_Test.php
index c1503b9d8e..3c96976d09 100644
--- a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/HeadingTest.php
+++ b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Heading_Test.php
@@ -2,10 +2,10 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\EmailEditor;
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Email_Editor;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class HeadingTest extends \MailPoetTest {
+class Heading_Test extends \MailPoetTest {
   /** @var Text */
   private $headingRenderer;
 
@@ -34,13 +34,13 @@ class HeadingTest extends \MailPoetTest {
     ],
   ];
 
-  /** @var SettingsController */
+  /** @var Settings_Controller */
   private $settingsController;
 
   public function _before() {
-    $this->diContainer->get(EmailEditor::class)->initialize();
+    $this->diContainer->get(Email_Editor::class)->initialize();
     $this->headingRenderer = new Text();
-    $this->settingsController = $this->diContainer->get(SettingsController::class);
+    $this->settingsController = $this->diContainer->get(Settings_Controller::class);
   }
 
   public function testItRendersContent(): void {
diff --git a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ImageTest.php b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Image_Test.php
similarity index 96%
rename from packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ImageTest.php
rename to packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Image_Test.php
index 48796802cb..ae2fb12ff7 100644
--- a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ImageTest.php
+++ b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Image_Test.php
@@ -2,10 +2,10 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\EmailEditor;
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Email_Editor;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class ImageTest extends \MailPoetTest {
+class Image_Test extends \MailPoetTest {
   /** @var Image */
   private $imageRenderer;
 
@@ -32,13 +32,13 @@ class ImageTest extends \MailPoetTest {
     'innerContent' => [],
   ];
 
-  /** @var SettingsController */
+  /** @var Settings_Controller */
   private $settingsController;
 
   public function _before() {
-    $this->diContainer->get(EmailEditor::class)->initialize();
+    $this->diContainer->get(Email_Editor::class)->initialize();
     $this->imageRenderer = new Image();
-    $this->settingsController = $this->diContainer->get(SettingsController::class);
+    $this->settingsController = $this->diContainer->get(Settings_Controller::class);
   }
 
   public function testItRendersMandatoryImageStyles(): void {
diff --git a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ListBlockTest.php b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/List_Block_Test.php
similarity index 87%
rename from packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ListBlockTest.php
rename to packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/List_Block_Test.php
index 44bedf1cc5..48129ef318 100644
--- a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ListBlockTest.php
+++ b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/List_Block_Test.php
@@ -2,11 +2,11 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\EmailEditor;
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Email_Editor;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class ListBlockTest extends \MailPoetTest {
-  /** @var ListBlock */
+class List_Block_Test extends \MailPoetTest {
+  /** @var List_Block */
   private $listRenderer;
 
   /** @var array */
@@ -41,13 +41,13 @@ class ListBlockTest extends \MailPoetTest {
     ],
   ];
 
-  /** @var SettingsController */
+  /** @var Settings_Controller */
   private $settingsController;
 
   public function _before() {
-    $this->diContainer->get(EmailEditor::class)->initialize();
-    $this->listRenderer = new ListBlock();
-    $this->settingsController = $this->diContainer->get(SettingsController::class);
+    $this->diContainer->get(Email_Editor::class)->initialize();
+    $this->listRenderer = new List_Block();
+    $this->settingsController = $this->diContainer->get(Settings_Controller::class);
   }
 
   public function testItRendersListContent(): void {
diff --git a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ParagraphTest.php b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Paragraph_Test.php
similarity index 95%
rename from packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ParagraphTest.php
rename to packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Paragraph_Test.php
index c3df082b5d..4cd15f3e8e 100644
--- a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/ParagraphTest.php
+++ b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Blocks/Paragraph_Test.php
@@ -2,10 +2,10 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer\Blocks;
 
-use MailPoet\EmailEditor\Engine\EmailEditor;
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Email_Editor;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class ParagraphTest extends \MailPoetTest {
+class Paragraph_Test extends \MailPoetTest {
   /** @var Text */
   private $paragraphRenderer;
 
@@ -26,13 +26,13 @@ class ParagraphTest extends \MailPoetTest {
      ],
   ];
 
-  /** @var SettingsController */
+  /** @var Settings_Controller */
   private $settingsController;
 
   public function _before() {
-    $this->diContainer->get(EmailEditor::class)->initialize();
+    $this->diContainer->get(Email_Editor::class)->initialize();
     $this->paragraphRenderer = new Text();
-    $this->settingsController = $this->diContainer->get(SettingsController::class);
+    $this->settingsController = $this->diContainer->get(Settings_Controller::class);
   }
 
   public function testItRendersContent(): void {
diff --git a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/RendererTest.php b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Renderer_Test.php
similarity index 98%
rename from packages/php/email-editor/tests/integration/Integrations/Core/Renderer/RendererTest.php
rename to packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Renderer_Test.php
index 7d321bd01f..3d677b9081 100644
--- a/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/RendererTest.php
+++ b/packages/php/email-editor/tests/integration/Integrations/Core/Renderer/Renderer_Test.php
@@ -2,18 +2,18 @@
 
 namespace MailPoet\EmailEditor\Integrations\Core\Renderer;
 
-use MailPoet\EmailEditor\Engine\EmailEditor;
+use MailPoet\EmailEditor\Engine\Email_Editor;
 use MailPoet\EmailEditor\Engine\Renderer\Renderer;
 use MailPoet\EmailEditor\Integrations\Core\Initializer;
 
-class RendererTest extends \MailPoetTest {
+class Renderer_Test extends \MailPoetTest {
   /** @var Renderer */
   private $renderer;
 
   public function _before() {
     parent::_before();
     $this->renderer = $this->diContainer->get(Renderer::class);
-    $this->diContainer->get(EmailEditor::class)->initialize();
+    $this->diContainer->get(Email_Editor::class)->initialize();
     $this->diContainer->get(Initializer::class)->initialize();
   }
 
diff --git a/packages/php/email-editor/tests/integration/_bootstrap.php b/packages/php/email-editor/tests/integration/_bootstrap.php
index 9ba47da82b..c2128250df 100644
--- a/packages/php/email-editor/tests/integration/_bootstrap.php
+++ b/packages/php/email-editor/tests/integration/_bootstrap.php
@@ -2,27 +2,27 @@
 
 use Codeception\Stub;
 use MailPoet\EmailEditor\Container;
-use MailPoet\EmailEditor\Engine\EmailApiController;
-use MailPoet\EmailEditor\Engine\EmailEditor;
+use MailPoet\EmailEditor\Engine\Email_Api_Controller;
+use MailPoet\EmailEditor\Engine\Email_Editor;
 use MailPoet\EmailEditor\Engine\Patterns\Patterns;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\BlocksRegistry;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\ContentRenderer;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\HighlightingPostprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\VariablesPostprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\BlocksWidthPreprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\CleanupPreprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\SpacingPreprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\TypographyPreprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\ProcessManager;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Blocks_Registry;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Content_Renderer;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\Highlighting_Postprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\Variables_Postprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Blocks_Width_Preprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Cleanup_Preprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Spacing_Preprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Typography_Preprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Process_Manager;
 use MailPoet\EmailEditor\Engine\Renderer\Renderer;
-use MailPoet\EmailEditor\Engine\SettingsController;
-use MailPoet\EmailEditor\Engine\Templates\TemplatePreview;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
+use MailPoet\EmailEditor\Engine\Templates\Template_Preview;
 use MailPoet\EmailEditor\Engine\Templates\Templates;
 use MailPoet\EmailEditor\Engine\Templates\Utils;
-use MailPoet\EmailEditor\Engine\ThemeController;
+use MailPoet\EmailEditor\Engine\Theme_Controller;
 use MailPoet\EmailEditor\Integrations\Core\Initializer;
 use MailPoet\EmailEditor\Integrations\MailPoet\Blocks\BlockTypesController;
-use MailPoet\EmailEditor\Utils\CdnAssetUrl;
+use MailPoet\EmailEditor\Utils\Cdn_Asset_Url;
 
 if ((boolean)getenv('MULTISITE') === true) {
   // REQUEST_URI needs to be set for WP to load the proper subsite where MailPoet is activated
@@ -81,11 +81,11 @@ abstract class MailPoetTest extends \Codeception\TestCase\Test { // phpcs:ignore
     $container->set(Initializer::class, function() {
       return new Initializer();
     });
-    $container->set(CdnAssetUrl::class, function() {
-      return new CdnAssetUrl('http://localhost');
+    $container->set(Cdn_Asset_Url::class, function() {
+      return new Cdn_Asset_Url('http://localhost');
     });
-    $container->set(EmailApiController::class, function() {
-      return new EmailApiController();
+    $container->set(Email_Api_Controller::class, function() {
+      return new Email_Api_Controller();
     });
     $container->set(BlockTypesController::class, function() {
       return $this->createMock(BlockTypesController::class);
@@ -94,83 +94,83 @@ abstract class MailPoetTest extends \Codeception\TestCase\Test { // phpcs:ignore
     $container->set(Utils::class, function() {
       return new Utils();
     });
-    $container->set(ThemeController::class, function() {
-      return new ThemeController();
+    $container->set(Theme_Controller::class, function() {
+      return new Theme_Controller();
     });
-    $container->set(SettingsController::class, function ($container) {
-      return new SettingsController($container->get(ThemeController::class));
+    $container->set(Settings_Controller::class, function ($container) {
+      return new Settings_Controller($container->get(Theme_Controller::class));
     });
-    $container->set(SettingsController::class, function ($container) {
-      return new SettingsController($container->get(ThemeController::class));
+    $container->set(Settings_Controller::class, function ($container) {
+      return new Settings_Controller($container->get(Theme_Controller::class));
     });
     $container->set(Templates::class, function ($container) {
       return new Templates($container->get(Utils::class));
     });
-    $container->set(TemplatePreview::class, function ($container) {
-      return new TemplatePreview(
-        $container->get(ThemeController::class),
-        $container->get(SettingsController::class),
+    $container->set(Template_Preview::class, function ($container) {
+      return new Template_Preview(
+        $container->get(Theme_Controller::class),
+        $container->get(Settings_Controller::class),
         $container->get(Templates::class),
       );
     });
     $container->set(Patterns::class, function ($container) {
       return new Patterns(
-        $container->get(CdnAssetUrl::class),
+        $container->get(Cdn_Asset_Url::class),
       );
     });
-    $container->set(CleanupPreprocessor::class, function () {
-      return new CleanupPreprocessor();
+    $container->set(Cleanup_Preprocessor::class, function () {
+      return new Cleanup_Preprocessor();
     });
-    $container->set(BlocksWidthPreprocessor::class, function () {
-      return new BlocksWidthPreprocessor();
+    $container->set(Blocks_Width_Preprocessor::class, function () {
+      return new Blocks_Width_Preprocessor();
     });
-    $container->set(TypographyPreprocessor::class, function ($container) {
-      return new TypographyPreprocessor($container->get(SettingsController::class));
+    $container->set(Typography_Preprocessor::class, function ($container) {
+      return new Typography_Preprocessor($container->get(Settings_Controller::class));
     });
-    $container->set(SpacingPreprocessor::class, function () {
-      return new SpacingPreprocessor();
+    $container->set(Spacing_Preprocessor::class, function () {
+      return new Spacing_Preprocessor();
     });
-    $container->set(HighlightingPostprocessor::class, function () {
-      return new HighlightingPostprocessor();
+    $container->set(Highlighting_Postprocessor::class, function () {
+      return new Highlighting_Postprocessor();
     });
-    $container->set(VariablesPostprocessor::class, function ($container) {
-      return new VariablesPostprocessor($container->get(ThemeController::class));
+    $container->set(Variables_Postprocessor::class, function ($container) {
+      return new Variables_Postprocessor($container->get(Theme_Controller::class));
     });
-    $container->set(ProcessManager::class, function ($container) {
-      return new ProcessManager(
-        $container->get(CleanupPreprocessor::class),
-        $container->get(BlocksWidthPreprocessor::class),
-        $container->get(TypographyPreprocessor::class),
-        $container->get(SpacingPreprocessor::class),
-        $container->get(HighlightingPostprocessor::class),
-        $container->get(VariablesPostprocessor::class),
+    $container->set(Process_Manager::class, function ($container) {
+      return new Process_Manager(
+        $container->get(Cleanup_Preprocessor::class),
+        $container->get(Blocks_Width_Preprocessor::class),
+        $container->get(Typography_Preprocessor::class),
+        $container->get(Spacing_Preprocessor::class),
+        $container->get(Highlighting_Postprocessor::class),
+        $container->get(Variables_Postprocessor::class),
       );
     });
-    $container->set(BlocksRegistry::class, function() {
-      return new BlocksRegistry();
+    $container->set(Blocks_Registry::class, function() {
+      return new Blocks_Registry();
     });
-    $container->set(ContentRenderer::class, function ($container) {
-      return new ContentRenderer(
-        $container->get(ProcessManager::class),
-        $container->get(BlocksRegistry::class),
-        $container->get(SettingsController::class),
-        $container->get(ThemeController::class),
+    $container->set(Content_Renderer::class, function ($container) {
+      return new Content_Renderer(
+        $container->get(Process_Manager::class),
+        $container->get(Blocks_Registry::class),
+        $container->get(Settings_Controller::class),
+        $container->get(Theme_Controller::class),
       );
     });
     $container->set(Renderer::class, function ($container) {
       return new Renderer(
-        $container->get(ContentRenderer::class),
+        $container->get(Content_Renderer::class),
         $container->get(Templates::class),
-        $container->get(ThemeController::class),
+        $container->get(Theme_Controller::class),
       );
     });
-    $container->set(EmailEditor::class, function ($container) {
-      return new EmailEditor(
-        $container->get(EmailApiController::class),
+    $container->set(Email_Editor::class, function ($container) {
+      return new Email_Editor(
+        $container->get(Email_Api_Controller::class),
         $container->get(Templates::class),
-        $container->get(TemplatePreview::class),
+        $container->get(Template_Preview::class),
         $container->get(Patterns::class),
-        $container->get(SettingsController::class),
+        $container->get(Settings_Controller::class),
       );
     });
 
diff --git a/packages/php/email-editor/tests/unit/ContainerTest.php b/packages/php/email-editor/tests/unit/Container_Test.php
similarity index 96%
rename from packages/php/email-editor/tests/unit/ContainerTest.php
rename to packages/php/email-editor/tests/unit/Container_Test.php
index 06e3f8e8f9..80fb3e304a 100644
--- a/packages/php/email-editor/tests/unit/ContainerTest.php
+++ b/packages/php/email-editor/tests/unit/Container_Test.php
@@ -6,7 +6,7 @@ use Exception;
 use PHPUnit\Framework\TestCase;
 use stdClass;
 
-class ContainerTest extends TestCase {
+class Container_Test extends TestCase {
   public function testSetAndGetService(): void {
     $container = new Container();
 
diff --git a/packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/HighlightingPostprocessorTest.php b/packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/Highlighting_Postprocessor_Test.php
similarity index 79%
rename from packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/HighlightingPostprocessorTest.php
rename to packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/Highlighting_Postprocessor_Test.php
index 0757b5bb16..52df145a72 100644
--- a/packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/HighlightingPostprocessorTest.php
+++ b/packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/Highlighting_Postprocessor_Test.php
@@ -2,15 +2,15 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\Postprocessors;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\HighlightingPostprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\Highlighting_Postprocessor;
 
-class HighlightingPostprocessorTest extends \MailPoetUnitTest {
-  /** @var HighlightingPostprocessor */
+class Highlighting_Postprocessor_Test extends \MailPoetUnitTest {
+  /** @var Highlighting_Postprocessor */
   private $postprocessor;
 
   public function _before() {
     parent::_before();
-    $this->postprocessor = new HighlightingPostprocessor();
+    $this->postprocessor = new Highlighting_Postprocessor();
   }
 
   public function testItReplacesHtmlElements(): void {
diff --git a/packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/VariablesPostprocessorTest.php b/packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/Variables_Postprocessor_Test.php
similarity index 73%
rename from packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/VariablesPostprocessorTest.php
rename to packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/Variables_Postprocessor_Test.php
index 284cf75da1..28bf42ea89 100644
--- a/packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/VariablesPostprocessorTest.php
+++ b/packages/php/email-editor/tests/unit/Engine/Renderer/Postprocessors/Variables_Postprocessor_Test.php
@@ -2,20 +2,20 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\Postprocessors;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\VariablesPostprocessor;
-use MailPoet\EmailEditor\Engine\ThemeController;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\Variables_Postprocessor;
+use MailPoet\EmailEditor\Engine\Theme_Controller;
 use PHPUnit\Framework\MockObject\MockObject;
 
-class VariablesPostprocessorTest extends \MailPoetUnitTest {
-  private VariablesPostprocessor $postprocessor;
+class Variables_Postprocessor_Test extends \MailPoetUnitTest {
+  private Variables_Postprocessor $postprocessor;
 
-  /** @var ThemeController & MockObject */
+  /** @var Theme_Controller & MockObject */
   private $themeControllerMock;
 
   public function _before() {
     parent::_before();
-    $this->themeControllerMock = $this->createMock(ThemeController::class);
-    $this->postprocessor = new VariablesPostprocessor($this->themeControllerMock);
+    $this->themeControllerMock = $this->createMock(Theme_Controller::class);
+    $this->postprocessor = new Variables_Postprocessor($this->themeControllerMock);
   }
 
   public function testItReplacesVariablesInStyleAttributes(): void {
diff --git a/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/BlocksWidthPreprocessorTest.php b/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Blocks_Width_Preprocessor_Test.php
similarity index 98%
rename from packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/BlocksWidthPreprocessorTest.php
rename to packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Blocks_Width_Preprocessor_Test.php
index 4d8d35d7d0..3529654360 100644
--- a/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/BlocksWidthPreprocessorTest.php
+++ b/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Blocks_Width_Preprocessor_Test.php
@@ -2,11 +2,11 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\Preprocessors;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\BlocksWidthPreprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Blocks_Width_Preprocessor;
 
-class BlocksWidthPreprocessorTest extends \MailPoetUnitTest {
+class Blocks_Width_Preprocessor_Test extends \MailPoetUnitTest {
 
-  /** @var BlocksWidthPreprocessor */
+  /** @var Blocks_Width_Preprocessor */
   private $preprocessor;
 
   /** @var array{contentSize: string} */
@@ -17,7 +17,7 @@ class BlocksWidthPreprocessorTest extends \MailPoetUnitTest {
 
   public function _before() {
     parent::_before();
-    $this->preprocessor = new BlocksWidthPreprocessor();
+    $this->preprocessor = new Blocks_Width_Preprocessor();
     $this->layout = ['contentSize' => '660px'];
     $this->styles = ['spacing' => ['padding' => ['left' => '10px', 'right' => '10px', 'top' => '10px', 'bottom' => '10px'], 'blockGap' => '10px']];
   }
diff --git a/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/CleanupPreprocessorTest.php b/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Cleanup_Preprocessor_Test.php
similarity index 91%
rename from packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/CleanupPreprocessorTest.php
rename to packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Cleanup_Preprocessor_Test.php
index 36bcb1229c..992ffb86fd 100644
--- a/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/CleanupPreprocessorTest.php
+++ b/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Cleanup_Preprocessor_Test.php
@@ -2,9 +2,9 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\Preprocessors;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\CleanupPreprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Cleanup_Preprocessor;
 
-class CleanupPreprocessorTest extends \MailPoetUnitTest {
+class Cleanup_Preprocessor_Test extends \MailPoetUnitTest {
 
   private const PARAGRAPH_BLOCK = [
     'blockName' => 'core/paragraph',
@@ -22,7 +22,7 @@ class CleanupPreprocessorTest extends \MailPoetUnitTest {
     ]],
   ];
 
-  /** @var CleanupPreprocessor */
+  /** @var Cleanup_Preprocessor */
   private $preprocessor;
 
   /** @var array{contentSize: string} */
@@ -33,7 +33,7 @@ class CleanupPreprocessorTest extends \MailPoetUnitTest {
 
   public function _before() {
     parent::_before();
-    $this->preprocessor = new CleanupPreprocessor();
+    $this->preprocessor = new Cleanup_Preprocessor();
     $this->layout = ['contentSize' => '660px'];
     $this->styles = ['spacing' => ['padding' => ['left' => '10px', 'right' => '10px', 'top' => '10px', 'bottom' => '10px'], 'blockGap' => '10px']];
   }
diff --git a/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/SpacingPreprocessorTest.php b/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Spacing_Preprocessor_Test.php
similarity index 93%
rename from packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/SpacingPreprocessorTest.php
rename to packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Spacing_Preprocessor_Test.php
index 84ade70b26..c99c8dffbd 100644
--- a/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/SpacingPreprocessorTest.php
+++ b/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Spacing_Preprocessor_Test.php
@@ -2,11 +2,11 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\Preprocessors;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\SpacingPreprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Spacing_Preprocessor;
 
-class SpacingPreprocessorTest extends \MailPoetUnitTest {
+class Spacing_Preprocessor_Test extends \MailPoetUnitTest {
 
-  /** @var SpacingPreprocessor */
+  /** @var Spacing_Preprocessor */
   private $preprocessor;
 
   /** @var array{contentSize: string} */
@@ -17,7 +17,7 @@ class SpacingPreprocessorTest extends \MailPoetUnitTest {
 
   public function _before() {
     parent::_before();
-    $this->preprocessor = new SpacingPreprocessor();
+    $this->preprocessor = new Spacing_Preprocessor();
     $this->layout = ['contentSize' => '660px'];
     $this->styles = ['spacing' => ['padding' => ['left' => '10px', 'right' => '10px', 'top' => '10px', 'bottom' => '10px'], 'blockGap' => '10px']];
   }
diff --git a/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/TypographyPreprocessorTest.php b/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Typography_Preprocessor_Test.php
similarity index 96%
rename from packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/TypographyPreprocessorTest.php
rename to packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Typography_Preprocessor_Test.php
index dadcf0728e..95f1c2ef89 100644
--- a/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/TypographyPreprocessorTest.php
+++ b/packages/php/email-editor/tests/unit/Engine/Renderer/Preprocessors/Typography_Preprocessor_Test.php
@@ -2,12 +2,12 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer\Preprocessors;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\TypographyPreprocessor;
-use MailPoet\EmailEditor\Engine\SettingsController;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Typography_Preprocessor;
+use MailPoet\EmailEditor\Engine\Settings_Controller;
 
-class TypographyPreprocessorTest extends \MailPoetUnitTest {
+class Typography_Preprocessor_Test extends \MailPoetUnitTest {
 
-  /** @var TypographyPreprocessor */
+  /** @var Typography_Preprocessor */
   private $preprocessor;
 
   /** @var array{contentSize: string} */
@@ -18,7 +18,7 @@ class TypographyPreprocessorTest extends \MailPoetUnitTest {
 
   public function _before() {
     parent::_before();
-    $settingsMock = $this->createMock(SettingsController::class);
+    $settingsMock = $this->createMock(Settings_Controller::class);
     $themeMock = $this->createMock(\WP_Theme_JSON::class);
     $themeMock->method('get_data')->willReturn([
       'styles' => [
@@ -52,7 +52,7 @@ class TypographyPreprocessorTest extends \MailPoetUnitTest {
     $settingsMock->method('translateSlugToFontSize')->willReturnCallback(function($slug) {
       return str_replace('slug-', '', $slug);
     });
-    $this->preprocessor = new TypographyPreprocessor($settingsMock);
+    $this->preprocessor = new Typography_Preprocessor($settingsMock);
     $this->layout = ['contentSize' => '660px'];
     $this->styles = ['spacing' => ['padding' => ['left' => '10px', 'right' => '10px', 'top' => '10px', 'bottom' => '10px'], 'blockGap' => '10px']];
   }
diff --git a/packages/php/email-editor/tests/unit/Engine/Renderer/ProcessManagerTest.php b/packages/php/email-editor/tests/unit/Engine/Renderer/Process_Manager_Test.php
similarity index 65%
rename from packages/php/email-editor/tests/unit/Engine/Renderer/ProcessManagerTest.php
rename to packages/php/email-editor/tests/unit/Engine/Renderer/Process_Manager_Test.php
index f046356cf1..264f010a78 100644
--- a/packages/php/email-editor/tests/unit/Engine/Renderer/ProcessManagerTest.php
+++ b/packages/php/email-editor/tests/unit/Engine/Renderer/Process_Manager_Test.php
@@ -2,15 +2,15 @@
 
 namespace MailPoet\EmailEditor\Engine\Renderer;
 
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\HighlightingPostprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\VariablesPostprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\BlocksWidthPreprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\CleanupPreprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\SpacingPreprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\TypographyPreprocessor;
-use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\ProcessManager;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\Highlighting_Postprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Postprocessors\Variables_Postprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Blocks_Width_Preprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Cleanup_Preprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Spacing_Preprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Preprocessors\Typography_Preprocessor;
+use MailPoet\EmailEditor\Engine\Renderer\ContentRenderer\Process_Manager;
 
-class ProcessManagerTest extends \MailPoetUnitTest {
+class Process_Manager_Test extends \MailPoetUnitTest {
   public function testItCallsPreprocessorsProperly(): void {
     $layout = [
       'contentSize' => '600px',
@@ -27,25 +27,25 @@ class ProcessManagerTest extends \MailPoetUnitTest {
       ],
     ];
 
-    $cleanup = $this->createMock(CleanupPreprocessor::class);
+    $cleanup = $this->createMock(Cleanup_Preprocessor::class);
     $cleanup->expects($this->once())->method('preprocess')->willReturn([]);
 
-    $blocksWidth = $this->createMock(BlocksWidthPreprocessor::class);
+    $blocksWidth = $this->createMock(Blocks_Width_Preprocessor::class);
     $blocksWidth->expects($this->once())->method('preprocess')->willReturn([]);
 
-    $typography = $this->createMock(TypographyPreprocessor::class);
+    $typography = $this->createMock(Typography_Preprocessor::class);
     $typography->expects($this->once())->method('preprocess')->willReturn([]);
 
-    $spacing = $this->createMock(SpacingPreprocessor::class);
+    $spacing = $this->createMock(Spacing_Preprocessor::class);
     $spacing->expects($this->once())->method('preprocess')->willReturn([]);
 
-    $highlighting = $this->createMock(HighlightingPostprocessor::class);
+    $highlighting = $this->createMock(Highlighting_Postprocessor::class);
     $highlighting->expects($this->once())->method('postprocess')->willReturn('');
 
-    $variables = $this->createMock(VariablesPostprocessor::class);
+    $variables = $this->createMock(Variables_Postprocessor::class);
     $variables->expects($this->once())->method('postprocess')->willReturn('');
 
-    $processManager = new ProcessManager($cleanup, $blocksWidth, $typography, $spacing, $highlighting, $variables);
+    $processManager = new Process_Manager($cleanup, $blocksWidth, $typography, $spacing, $highlighting, $variables);
     $this->assertEquals([], $processManager->preprocess([], $layout, $styles));
     $this->assertEmpty($processManager->postprocess(''));
   }
diff --git a/packages/php/email-editor/tests/unit/Engine/SettingsControllerTest.php b/packages/php/email-editor/tests/unit/Engine/Settings_Controller_Test.php
similarity index 82%
rename from packages/php/email-editor/tests/unit/Engine/SettingsControllerTest.php
rename to packages/php/email-editor/tests/unit/Engine/Settings_Controller_Test.php
index 8c50468633..289f413ab0 100644
--- a/packages/php/email-editor/tests/unit/Engine/SettingsControllerTest.php
+++ b/packages/php/email-editor/tests/unit/Engine/Settings_Controller_Test.php
@@ -2,7 +2,7 @@
 
 namespace MailPoet\EmailEditor\Engine;
 
-class SettingsControllerTest extends \MailPoetUnitTest {
+class Settings_Controller_Test extends \MailPoetUnitTest {
   public function testItGetsCorrectLayoutWidthWithoutPadding(): void {
     $themeJsonMock = $this->createMock(\WP_Theme_JSON::class);
     $themeJsonMock->method('get_data')->willReturn([
@@ -15,13 +15,13 @@ class SettingsControllerTest extends \MailPoetUnitTest {
         ],
       ],
     ]);
-    $themeController = $this->createMock(ThemeController::class);
+    $themeController = $this->createMock(Theme_Controller::class);
     $themeController->method('getTheme')->willReturn($themeJsonMock);
     $themeController->method('getLayoutSettings')->willReturn([
       "contentSize" => "660px",
       "wideSize" => null,
     ]);
-    $settingsController = new SettingsController($themeController);
+    $settingsController = new Settings_Controller($themeController);
     $layoutWidth = $settingsController->getLayoutWidthWithoutPadding();
     // default width is 660px and if we subtract padding from left and right we must get the correct value
     $expectedWidth = 660 - 10 * 2;
diff --git a/packages/php/email-editor/tests/unit/Integrations/Utils/DomDocumentHelperTest.php b/packages/php/email-editor/tests/unit/Integrations/Utils/Dom_Document_Helper_Test.php
similarity index 84%
rename from packages/php/email-editor/tests/unit/Integrations/Utils/DomDocumentHelperTest.php
rename to packages/php/email-editor/tests/unit/Integrations/Utils/Dom_Document_Helper_Test.php
index d2a7ddf6f5..a4b875b27e 100644
--- a/packages/php/email-editor/tests/unit/Integrations/Utils/DomDocumentHelperTest.php
+++ b/packages/php/email-editor/tests/unit/Integrations/Utils/Dom_Document_Helper_Test.php
@@ -2,10 +2,10 @@
 
 namespace MailPoet\EmailEditor\Integrations\Utils;
 
-class DomDocumentHelperTest extends \MailPoetUnitTest {
+class Dom_Document_Helper_Test extends \MailPoetUnitTest {
   public function testItFindsElement(): void {
     $html = '<div><p>Some text</p></div>';
-    $domDocumentHelper = new DomDocumentHelper($html);
+    $domDocumentHelper = new Dom_Document_Helper($html);
     $element = $domDocumentHelper->findElement('p');
     $empty = $domDocumentHelper->findElement('span');
     $this->assertInstanceOf(\DOMElement::class, $element);
@@ -15,7 +15,7 @@ class DomDocumentHelperTest extends \MailPoetUnitTest {
 
   public function testItGetsAttributeValue(): void {
     $html = '<div><p class="some-class">Some text</p></div>';
-    $domDocumentHelper = new DomDocumentHelper($html);
+    $domDocumentHelper = new Dom_Document_Helper($html);
     $element = $domDocumentHelper->findElement('p');
     $this->assertInstanceOf(\DOMElement::class, $element);
     $this->assertEquals('some-class', $domDocumentHelper->getAttributeValue($element, 'class'));
@@ -23,14 +23,14 @@ class DomDocumentHelperTest extends \MailPoetUnitTest {
 
   public function testItGetsOuterHtml(): void {
     $html = '<div><span>Some <strong>text</strong></span></div>';
-    $domDocumentHelper = new DomDocumentHelper($html);
+    $domDocumentHelper = new Dom_Document_Helper($html);
     $element = $domDocumentHelper->findElement('span');
     $this->assertInstanceOf(\DOMElement::class, $element);
     $this->assertEquals('<span>Some <strong>text</strong></span>', $domDocumentHelper->getOuterHtml($element));
 
     // testings encoding of special characters
     $html = '<div><img src="https://test.com/DALL·E-A®∑oecasƒ-803x1024.jpg"></div>';
-    $domDocumentHelper = new DomDocumentHelper($html);
+    $domDocumentHelper = new Dom_Document_Helper($html);
     $element = $domDocumentHelper->findElement('img');
     $this->assertInstanceOf(\DOMElement::class, $element);
     $this->assertEquals('<img src="https://test.com/DALL%C2%B7E-A%C2%AE%E2%88%91oecas%C6%92-803x1024.jpg">', $domDocumentHelper->getOuterHtml($element));
@@ -38,7 +38,7 @@ class DomDocumentHelperTest extends \MailPoetUnitTest {
 
   public function testItGetsAttributeValueByTagName(): void {
     $html = '<div><p class="some-class">Some text</p><p class="second-paragraph"></p></div>';
-    $domDocumentHelper = new DomDocumentHelper($html);
+    $domDocumentHelper = new Dom_Document_Helper($html);
     $this->assertEquals('some-class', $domDocumentHelper->getAttributeValueByTagName('p', 'class'));
     $this->assertNull($domDocumentHelper->getAttributeValueByTagName('span', 'class'));
   }