diff --git a/mailpoet/lib/API/JSON/v1/SendingQueue.php b/mailpoet/lib/API/JSON/v1/SendingQueue.php
index 688f8206a1..8572717091 100644
--- a/mailpoet/lib/API/JSON/v1/SendingQueue.php
+++ b/mailpoet/lib/API/JSON/v1/SendingQueue.php
@@ -13,7 +13,6 @@ use MailPoet\Entities\NewsletterEntity;
 use MailPoet\Entities\ScheduledTaskEntity;
 use MailPoet\Entities\SendingQueueEntity;
 use MailPoet\Mailer\MailerFactory;
-use MailPoet\Models\Newsletter;
 use MailPoet\Models\SendingQueue as SendingQueueModel;
 use MailPoet\Newsletter\NewslettersRepository;
 use MailPoet\Newsletter\NewsletterValidator;
@@ -96,21 +95,16 @@ class SendingQueue extends APIEndpoint {
     );
 
     // check that the newsletter exists
-    $newsletter = Newsletter::findOneWithOptions($newsletterId);
+    $newsletter = $this->newsletterRepository->findOneById($newsletterId);
+    $this->newsletterRepository->prefetchOptions([$newsletter]);
 
-    if (!$newsletter instanceof Newsletter) {
-      return $this->errorResponse([
-        APIError::NOT_FOUND => __('This newsletter does not exist.', 'mailpoet'),
-      ]);
-    }
-    $newsletterEntity = $this->newsletterRepository->findOneById($newsletterId);
-    if (!$newsletterEntity instanceof NewsletterEntity) {
+    if (!$newsletter instanceof NewsletterEntity) {
       return $this->errorResponse([
         APIError::NOT_FOUND => __('This newsletter does not exist.', 'mailpoet'),
       ]);
     }
 
-    $validationError = $this->newsletterValidator->validate($newsletterEntity);
+    $validationError = $this->newsletterValidator->validate($newsletter);
     if ($validationError) {
       return $this->errorResponse([
         APIError::BAD_REQUEST => $validationError,
@@ -128,7 +122,7 @@ class SendingQueue extends APIEndpoint {
 
     // add newsletter to the sending queue
     $queue = SendingQueueModel::joinWithTasks()
-      ->where('queues.newsletter_id', $newsletterEntity->getId())
+      ->where('queues.newsletter_id', $newsletter->getId())
       ->whereNull('tasks.status')
       ->findOne();
 
@@ -139,31 +133,31 @@ class SendingQueue extends APIEndpoint {
     }
 
     $scheduledQueue = SendingQueueModel::joinWithTasks()
-      ->where('queues.newsletter_id', $newsletterEntity->getId())
+      ->where('queues.newsletter_id', $newsletter->getId())
       ->where('tasks.status', SendingQueueModel::STATUS_SCHEDULED)
       ->findOne();
     if ($scheduledQueue instanceof SendingQueueModel) {
       $queue = SendingTask::createFromQueue($scheduledQueue);
     } else {
       $queue = SendingTask::create();
-      $queue->newsletterId = $newsletterEntity->getId();
+      $queue->newsletterId = $newsletter->getId();
     }
 
     WordPress::resetRunInterval();
-    if ((bool)$newsletterEntity->getOptionValue('isScheduled')) {
+    if ((bool)$newsletter->getOptionValue('isScheduled')) {
       // set newsletter status
-      $newsletterEntity->setStatus(NewsletterEntity::STATUS_SCHEDULED);
+      $newsletter->setStatus(NewsletterEntity::STATUS_SCHEDULED);
 
       // set queue status
       $queue->status = SendingQueueModel::STATUS_SCHEDULED;
-      $queue->scheduledAt = $this->scheduler->formatDatetimeString($newsletterEntity->getOptionValue('scheduledAt'));
+      $queue->scheduledAt = $this->scheduler->formatDatetimeString($newsletter->getOptionValue('scheduledAt'));
     } else {
-      $segments = $newsletterEntity->getSegmentIds();
+      $segments = $newsletter->getSegmentIds();
       $taskModel = $queue->task();
       $taskEntity = $this->scheduledTasksRepository->findOneById($taskModel->id);
 
       if ($taskEntity instanceof ScheduledTaskEntity) {
-        $subscribersCount = $this->subscribersFinder->addSubscribersToTaskFromSegments($taskEntity, $segments, $newsletterEntity->getFilterSegmentId());
+        $subscribersCount = $this->subscribersFinder->addSubscribersToTaskFromSegments($taskEntity, $segments, $newsletter->getFilterSegmentId());
       }
 
       if (!isset($subscribersCount) || !$subscribersCount) {
@@ -176,7 +170,7 @@ class SendingQueue extends APIEndpoint {
       $queue->scheduledAt = null;
 
       // set newsletter status
-      $newsletterEntity->setStatus(Newsletter::STATUS_SENDING);
+      $newsletter->setStatus(NewsletterEntity::STATUS_SENDING);
     }
     $queue->save();
     $this->newsletterRepository->flush();
@@ -185,9 +179,9 @@ class SendingQueue extends APIEndpoint {
     if (!empty($errors)) {
       return $this->errorResponse($errors);
     } else {
-      $this->triggerSending($newsletterEntity);
+      $this->triggerSending($newsletter);
       return $this->successResponse(
-        $newsletter->getQueue()->asArray()
+        ($newsletter->getLatestQueue() instanceof SendingQueueEntity) ? $newsletter->getLatestQueue()->toArray() : null
       );
     }
   }
diff --git a/mailpoet/lib/Entities/SendingQueueEntity.php b/mailpoet/lib/Entities/SendingQueueEntity.php
index 8358dee6b1..f4dcc4e1b0 100644
--- a/mailpoet/lib/Entities/SendingQueueEntity.php
+++ b/mailpoet/lib/Entities/SendingQueueEntity.php
@@ -223,4 +223,36 @@ class SendingQueueEntity {
   public function setNewsletter(NewsletterEntity $newsletter) {
     $this->newsletter = $newsletter;
   }
+
+  public function toArray(): array {
+    if (!$this->getTask() instanceof ScheduledTaskEntity) {
+      throw new \RuntimeException('Invalid state. SendingQueue has ScheduledTask associated.');
+    }
+
+    return [
+      'id' => $this->getId(),
+      'type' => $this->getTask()->getType(),
+      'status' => $this->getTask()->getStatus(),
+      'priority' => $this->getTask()->getPriority(),
+      'scheduled_at' => $this->getFormattedDateOrNull($this->getTask()->getScheduledAt()),
+      'processed_at' => $this->getFormattedDateOrNull($this->getTask()->getProcessedAt()),
+      'created_at' => $this->getFormattedDateOrNull($this->getTask()->getCreatedAt()),
+      'updated_at' => $this->getFormattedDateOrNull($this->getTask()->getUpdatedAt()),
+      'deleted_at' => $this->getFormattedDateOrNull($this->getTask()->getDeletedAt()),
+      'in_progress' => $this->getTask()->getInProgress(),
+      'reschedule_count' => $this->getTask()->getRescheduleCount(),
+      'meta' => $this->getMeta(),
+      'task_id' => $this->getTask()->getId(),
+      'newsletter_id' => ($this->getNewsletter() instanceof NewsletterEntity) ? $this->getNewsletter()->getId() : null,
+      'newsletter_rendered_body' => $this->getNewsletterRenderedBody(),
+      'newsletter_rendered_subject' => $this->getNewsletterRenderedSubject(),
+      'count_total' => $this->getCountTotal(),
+      'count_processed' => $this->getCountProcessed(),
+      'count_to_process' => $this->getCountToProcess(),
+    ];
+  }
+
+  private function getFormattedDateOrNull(?\DateTimeInterface $date): ?string {
+    return $date ? $date->format('Y-m-d H:i:s') : null;
+  }
 }
diff --git a/mailpoet/tests/integration/Entities/SendingQueueEntityTest.php b/mailpoet/tests/integration/Entities/SendingQueueEntityTest.php
new file mode 100644
index 0000000000..33ced892e6
--- /dev/null
+++ b/mailpoet/tests/integration/Entities/SendingQueueEntityTest.php
@@ -0,0 +1,61 @@
+<?php declare(strict_types = 1);
+
+namespace integration\Entities;
+
+use MailPoet\Entities\NewsletterEntity;
+use MailPoet\Entities\ScheduledTaskEntity;
+use MailPoet\Entities\SendingQueueEntity;
+use MailPoet\Tasks\Sending;
+use MailPoet\Test\DataFactories\Newsletter as NewsletterFactory;
+use MailPoet\Test\DataFactories\ScheduledTask as ScheduledTaskFactory;
+use MailPoet\Test\DataFactories\SendingQueue as SendingQueueFactory;
+use MailPoetVendor\Carbon\Carbon;
+
+class SendingQueueEntityTest extends \MailPoetTest {
+  /** @var NewsletterEntity */
+  private $newsletter;
+
+  /** @var ScheduledTaskEntity */
+  private $scheduledTask;
+
+  /** @var SendingQueueEntity */
+  private $sendingQueue;
+
+  public function _before() {
+    $newsletterFactory = new NewsletterFactory();
+    $sendingQueueFactory = new SendingQueueFactory();
+    $scheduledTaskFactory = new ScheduledTaskFactory();
+
+    $scheduledAt = new Carbon('2018-10-10 10:00:00');
+    $this->newsletter = $newsletterFactory->create();
+    $this->scheduledTask = $scheduledTaskFactory->create(Sending::TASK_TYPE, ScheduledTaskEntity::STATUS_SCHEDULED, $scheduledAt);
+    $this->sendingQueue = $sendingQueueFactory->create($this->scheduledTask, $this->newsletter);
+    $this->assertInstanceOf(SendingQueueEntity::class, $this->sendingQueue);
+  }
+
+  public function testToArrayReturnsExpectedResult() {
+    $expectedResult = [
+      'id' => $this->sendingQueue->getId(),
+      'type' => 'sending',
+      'status' => 'scheduled',
+      'priority' => 0,
+      'scheduled_at' => '2018-10-10 10:00:00',
+      'processed_at' => null,
+      'created_at' => !is_null($this->sendingQueue->getCreatedAt()) ? $this->sendingQueue->getCreatedAt()->format('Y-m-d H:i:s') : null,
+      'updated_at' => $this->sendingQueue->getUpdatedAt()->format('Y-m-d H:i:s'),
+      'deleted_at' => null,
+      'in_progress' => null,
+      'reschedule_count' => 0,
+      'meta' => null,
+      'task_id' => $this->scheduledTask->getId(),
+      'newsletter_id' => $this->newsletter->getId(),
+      'newsletter_rendered_body' => null,
+      'newsletter_rendered_subject' => null,
+      'count_total' => 0,
+      'count_processed' => 0,
+      'count_to_process' => 0,
+    ];
+
+    $this->assertSame($expectedResult, $this->sendingQueue->toArray());
+  }
+}