diff --git a/lib/Doctrine/ConnectionFactory.php b/lib/Doctrine/ConnectionFactory.php
index 4584c3a8d1..cfd126b648 100644
--- a/lib/Doctrine/ConnectionFactory.php
+++ b/lib/Doctrine/ConnectionFactory.php
@@ -3,8 +3,11 @@
 namespace MailPoet\Doctrine;
 
 use MailPoet\Config\Env;
+use MailPoet\Doctrine\Types\JsonOrSerializedType;
+use MailPoet\Doctrine\Types\JsonType;
 use MailPoetVendor\Doctrine\DBAL\DriverManager;
 use MailPoetVendor\Doctrine\DBAL\Platforms\MySqlPlatform;
+use MailPoetVendor\Doctrine\DBAL\Types\Type;
 use PDO;
 
 class ConnectionFactory {
@@ -13,6 +16,11 @@ class ConnectionFactory {
 
   private $min_wait_timeout = 60;
 
+  private $types = [
+    JsonType::NAME => JsonType::class,
+    JsonOrSerializedType::NAME => JsonOrSerializedType::class,
+  ];
+
   function createConnection() {
     $platform_class = self::PLATFORM_CLASS;
     $connection_params = [
@@ -36,6 +44,7 @@ class ConnectionFactory {
       $connection_params['port'] = Env::$db_port;
     }
 
+    $this->setupTypes();
     return DriverManager::getConnection($connection_params);
   }
 
@@ -56,4 +65,14 @@ class ConnectionFactory {
       PDO::MYSQL_ATTR_INIT_COMMAND => 'SET ' . implode(', ', $driver_options),
     ];
   }
+
+  private function setupTypes() {
+    foreach ($this->types as $name => $class) {
+      if (Type::hasType($name)) {
+        Type::overrideType($name, $class);
+      } else {
+        Type::addType($name, $class);
+      }
+    }
+  }
 }
diff --git a/lib/Doctrine/Types/JsonOrSerializedType.php b/lib/Doctrine/Types/JsonOrSerializedType.php
new file mode 100644
index 0000000000..91294492a2
--- /dev/null
+++ b/lib/Doctrine/Types/JsonOrSerializedType.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace MailPoet\Doctrine\Types;
+
+use MailPoetVendor\Doctrine\DBAL\Platforms\AbstractPlatform;
+
+class JsonOrSerializedType extends JsonType {
+  const NAME = 'json_or_serialized';
+
+  function convertToPHPValue($value, AbstractPlatform $platform) {
+    if ($value === null) {
+      return null;
+    }
+
+    if (is_resource($value)) {
+      $value = stream_get_contents($value);
+    }
+
+    if (is_serialized($value)) {
+      return unserialize($value);
+    }
+    return parent::convertToPHPValue($value, $platform);
+  }
+
+  function getName() {
+    return self::NAME;
+  }
+}
diff --git a/lib/Doctrine/Types/JsonType.php b/lib/Doctrine/Types/JsonType.php
new file mode 100644
index 0000000000..c8998e183e
--- /dev/null
+++ b/lib/Doctrine/Types/JsonType.php
@@ -0,0 +1,58 @@
+<?php
+
+namespace MailPoet\Doctrine\Types;
+
+use MailPoetVendor\Doctrine\DBAL\Platforms\AbstractPlatform;
+use MailPoetVendor\Doctrine\DBAL\Types\Type;
+
+class JsonType extends Type {
+  const NAME = 'json';
+
+  function getSQLDeclaration(array $fieldDeclaration, AbstractPlatform $platform) {
+    return $platform->getJsonTypeDeclarationSQL($fieldDeclaration);
+  }
+
+  function convertToDatabaseValue($value, AbstractPlatform $platform) {
+    if ($value === null) {
+      return null;
+    }
+
+    $flags = JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES;
+    if (defined('JSON_PRESERVE_ZERO_FRACTION')) {
+      $flags |= JSON_PRESERVE_ZERO_FRACTION; // phpcs:ignore
+    }
+
+    $encoded = json_encode($value, $flags);
+    $this->handleErrors();
+    return $encoded;
+  }
+
+  function convertToPHPValue($value, AbstractPlatform $platform) {
+    if ($value === null) {
+      return null;
+    }
+
+    if (is_resource($value)) {
+      $value = stream_get_contents($value);
+    }
+
+    $decoded = json_decode($value, true);
+    $this->handleErrors();
+    return $decoded;
+  }
+
+  function getName() {
+    return self::NAME;
+  }
+
+  function requiresSQLCommentHint(AbstractPlatform $platform) {
+    return !$platform->hasNativeJsonType();
+  }
+
+  private function handleErrors() {
+    $error = json_last_error();
+    if ($error !== JSON_ERROR_NONE) {
+      throw new \RuntimeException(json_last_error_msg(), $error);
+    }
+  }
+}
diff --git a/tests/integration/Doctrine/ConnectionFactoryTest.php b/tests/integration/Doctrine/ConnectionFactoryTest.php
index 7957ee335b..c5ae3b3cd0 100644
--- a/tests/integration/Doctrine/ConnectionFactoryTest.php
+++ b/tests/integration/Doctrine/ConnectionFactoryTest.php
@@ -5,8 +5,11 @@ namespace MailPoet\Test\Config;
 use MailPoet\Config\Env;
 use MailPoet\Doctrine\ConnectionFactory;
 use MailPoet\Doctrine\SerializableConnection;
+use MailPoet\Doctrine\Types\JsonOrSerializedType;
+use MailPoet\Doctrine\Types\JsonType;
 use MailPoetVendor\Doctrine\DBAL\Driver\PDOMySql;
 use MailPoetVendor\Doctrine\DBAL\Platforms\MySqlPlatform;
+use MailPoetVendor\Doctrine\DBAL\Types\Type;
 use PDO;
 
 class ConnectionFactoryTest extends \MailPoetTest {
@@ -36,6 +39,9 @@ class ConnectionFactoryTest extends \MailPoetTest {
     expect($connection->getPassword())->equals(Env::$db_password);
     expect($connection->getParams()['charset'])->equals(Env::$db_charset);
     expect($connection->getDatabase())->equals(Env::$db_name);
+
+    expect(Type::getType(JsonType::NAME))->isInstanceOf(JsonType::class);
+    expect(Type::getType(JsonOrSerializedType::NAME))->isInstanceOf(JsonOrSerializedType::class);
   }
 
   function testItIgnoresEmptyCharset() {
diff --git a/tests/integration/Doctrine/Types/JsonEntity.php b/tests/integration/Doctrine/Types/JsonEntity.php
new file mode 100644
index 0000000000..f45ff27fd4
--- /dev/null
+++ b/tests/integration/Doctrine/Types/JsonEntity.php
@@ -0,0 +1,64 @@
+<?php
+
+namespace MailPoet\Test\Doctrine\Types;
+
+/**
+ * @Entity()
+ * @Table(name="test_json_entity")
+ */
+class JsonEntity {
+  /**
+   * @Column(type="integer")
+   * @Id
+   * @GeneratedValue
+   * @var int|null
+   */
+  private $id;
+
+  /**
+   * @Column(type="json")
+   * @var array|null
+   */
+  private $json_data;
+
+  /**
+   * @Column(type="json_or_serialized")
+   * @var array|null
+   */
+  private $json_or_serialized_data;
+
+  /**
+   * @return int|null
+   */
+  function getId() {
+    return $this->id;
+  }
+
+  /**
+   * @return array|null
+   */
+  public function getJsonData() {
+    return $this->json_data;
+  }
+
+  /**
+   * @param array|null $json_data
+   */
+  public function setJsonData($json_data) {
+    $this->json_data = $json_data;
+  }
+
+  /**
+   * @return array|null
+   */
+  public function getJsonOrSerializedData() {
+    return $this->json_or_serialized_data;
+  }
+
+  /**
+   * @param array|null $json_or_serialized_data
+   */
+  public function setJsonOrSerializedData($json_or_serialized_data) {
+    $this->json_or_serialized_data = $json_or_serialized_data;
+  }
+}
diff --git a/tests/integration/Doctrine/Types/JsonTypesTest.php b/tests/integration/Doctrine/Types/JsonTypesTest.php
new file mode 100644
index 0000000000..401e8279b6
--- /dev/null
+++ b/tests/integration/Doctrine/Types/JsonTypesTest.php
@@ -0,0 +1,164 @@
+<?php
+
+namespace MailPoet\Test\Doctrine\EventListeners;
+
+use Exception;
+use MailPoet\Doctrine\ConfigurationFactory;
+use MailPoet\Doctrine\EntityManagerFactory;
+use MailPoet\Doctrine\EventListeners\TimestampListener;
+use MailPoet\Test\Doctrine\Types\JsonEntity;
+use MailPoet\WP\Functions as WPFunctions;
+use MailPoetVendor\Doctrine\Common\Cache\ArrayCache;
+use RuntimeException;
+
+require_once __DIR__ . '/JsonEntity.php';
+
+class JsonTypesTest extends \MailPoetTest {
+  /** @var WPFunctions */
+  private $wp;
+
+  /** @var string */
+  private $table_name;
+
+  /** @var array */
+  private $test_data = [
+    'key' => [
+      'a' => 'string',
+      'b' => 10,
+      'c' => true,
+      'd' => null,
+    ],
+  ];
+
+  function _before() {
+    $this->wp = new WPFunctions();
+    $this->entity_manager = $this->createEntityManager();
+    $this->table_name = $this->entity_manager->getClassMetadata(JsonEntity::class)->getTableName();
+    $this->connection->executeUpdate("DROP TABLE IF EXISTS $this->table_name");
+    $this->connection->executeUpdate("
+      CREATE TABLE $this->table_name (
+        id int(11) unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY,
+        json_data longtext NULL,
+        json_or_serialized_data longtext NULL
+      )
+    ");
+  }
+
+  function testItSavesJsonData() {
+    $entity = new JsonEntity();
+    $entity->setJsonData($this->test_data);
+    $entity->setJsonOrSerializedData($this->test_data);
+    $this->entity_manager->persist($entity);
+    $this->entity_manager->flush();
+
+    $saved_data = $this->connection->executeQuery("SELECT * FROM $this->table_name")->fetch();
+    expect($saved_data['json_data'])->same(json_encode($this->test_data));
+    expect($saved_data['json_or_serialized_data'])->same(json_encode($this->test_data));
+  }
+
+  function testItLoadsJsonData() {
+    $this->connection->executeUpdate(
+      "INSERT INTO $this->table_name (id, json_data, json_or_serialized_data) VALUES (?, ?, ?)",
+      [
+        1,
+        json_encode($this->test_data),
+        json_encode($this->test_data),
+      ]
+    );
+
+    $entity = $this->entity_manager->find(JsonEntity::class, 1);
+    expect($entity->getJsonData())->same($this->test_data);
+    expect($entity->getJsonOrSerializedData())->same($this->test_data);
+  }
+
+  function testItLoadsSerializedData() {
+    $this->connection->executeUpdate(
+      "INSERT INTO $this->table_name (id, json_or_serialized_data) VALUES (?, ?)",
+      [
+        1,
+        serialize($this->test_data),
+      ]
+    );
+
+    $entity = $this->entity_manager->find(JsonEntity::class, 1);
+    expect($entity->getJsonData())->null();
+    expect($entity->getJsonOrSerializedData())->same($this->test_data);
+  }
+
+  function testItSavesNullData() {
+    $entity = new JsonEntity();
+    $entity->setJsonData(null);
+    $entity->setJsonOrSerializedData(null);
+    $this->entity_manager->persist($entity);
+    $this->entity_manager->flush();
+
+    $saved_data = $this->connection->executeQuery("SELECT * FROM $this->table_name")->fetch();
+    expect($saved_data['json_data'])->null();
+    expect($saved_data['json_or_serialized_data'])->null();
+  }
+
+  function testItLoadsNullData() {
+    $this->connection->executeUpdate(
+      "INSERT INTO $this->table_name (id, json_data, json_or_serialized_data) VALUES (?, ?, ?)",
+      [
+        1,
+        null,
+        null,
+      ]
+    );
+
+    $entity = $this->entity_manager->find(JsonEntity::class, 1);
+    expect($entity->getJsonData())->null();
+    expect($entity->getJsonOrSerializedData())->null();
+  }
+
+  function testItDoesNotSaveInvalidData() {
+    $entity = new JsonEntity();
+    $entity->setJsonData("\xB1\x31"); // invalid unicode sequence
+    $this->entity_manager->persist($entity);
+
+    $exception = null;
+    try {
+      $this->entity_manager->flush();
+    } catch (Exception $e) {
+      $exception = $e;
+    }
+    expect($exception)->isInstanceOf(RuntimeException::class);
+  }
+
+  function testItDoesNotLoadInvalidData() {
+    $this->connection->executeUpdate(
+      "INSERT INTO $this->table_name (id, json_data) VALUES (?, ?)",
+      [
+        1,
+        '{', // invalid JSON
+      ]
+    );
+
+    $exception = null;
+    try {
+      $this->entity_manager->find(JsonEntity::class, 1);
+    } catch (Exception $e) {
+      $exception = $e;
+    }
+    expect($exception)->isInstanceOf(RuntimeException::class);
+  }
+
+  function _after() {
+    parent::_after();
+    $this->connection->executeUpdate("DROP TABLE IF EXISTS $this->table_name");
+  }
+
+  private function createEntityManager() {
+    $configuration_factory = new ConfigurationFactory();
+    $configuration = $configuration_factory->createConfiguration();
+
+    $metadata_driver = $configuration->newDefaultAnnotationDriver([__DIR__]);
+    $configuration->setMetadataDriverImpl($metadata_driver);
+    $configuration->setMetadataCacheImpl(new ArrayCache());
+
+    $timestamp_listener = new TimestampListener($this->wp);
+    $entity_manager_factory = new EntityManagerFactory($this->connection, $configuration, $timestamp_listener);
+    return $entity_manager_factory->createEntityManager();
+  }
+}