diff --git a/inmail.module b/inmail.module
index 0820b52..a6494de 100644
--- a/inmail.module
+++ b/inmail.module
@@ -317,6 +317,15 @@ function inmail_mail($key, &$message, $params) {
       $header->addField('X-Inmail-Forwarded', 'handler_moderator_forward');
       $message['raw_headers'] = $header;
       break;
+    case 'success':
+      /** @var \Drupal\inmail\MIME\MessageInterface $result */
+      $original = $params['original'];
+      $message['subject'] = 'Re: ' . $original->getSubject();
+      $message['from'] = $original->getFrom();
+      $message['id'] = $original->getMessageId();
+      $message['cc'] = $original->getCc();
+      $message['body'] = 'Reply.';
+      break;
   }
 }
 
diff --git a/src/Form/PluginConfigurationForm.php b/src/Form/PluginConfigurationForm.php
index b7115dc..f48e280 100644
--- a/src/Form/PluginConfigurationForm.php
+++ b/src/Form/PluginConfigurationForm.php
@@ -29,11 +29,19 @@ class PluginConfigurationForm extends EntityForm {
   protected $storage;
 
   /**
+   * Send the whole log as message body.
+   *
+   * @var bool
+   */
+  protected $sendLog;
+
+  /**
    * {@inheritdoc}
    */
   public function __construct(PluginManagerInterface $plugin_manager, ConfigEntityStorageInterface $storage) {
     $this->pluginManager = $plugin_manager;
     $this->storage = $storage;
+    $this->sendLog = FALSE;
   }
 
   /**
@@ -66,6 +74,12 @@ class PluginConfigurationForm extends EntityForm {
       '#default_value' => $entity->status(),
     );
 
+    $form['log'] = [
+      '#title' => $this->t('Attache log'),
+      '#type' => 'checkbox',
+      '#default_value' => $this->sendLog,
+    ];
+
     $form['plugin_container'] = array(
       '#type' => 'container',
       '#prefix' => '<div id="inmail-plugin">',
@@ -191,6 +205,7 @@ class PluginConfigurationForm extends EntityForm {
       /** @var \Drupal\inmail\Entity\PluginConfigEntity $entity */
       $entity = $this->getEntity();
       $entity->setConfiguration($plugin->getConfiguration());
+      $this->sendLog = $form_state->get('log');
     }
   }
 
diff --git a/src/MessageProcessor.php b/src/MessageProcessor.php
index cd93b21..363942f 100644
--- a/src/MessageProcessor.php
+++ b/src/MessageProcessor.php
@@ -168,6 +168,13 @@ class MessageProcessor implements MessageProcessorInterface {
         }
       }
       $result->success($key);
+      // Trigger result transition mail.
+      $params['result'] = $result;
+      // Sending message.
+      $recipient = $message->getFrom();
+      $mail_manager = \Drupal::service('plugin.manager.mail');
+      $mail_manager->mail('inmail_success', 'success', $recipient, \Drupal::languageManager()->getDefaultLanguage()->getId(), $params);
+
     }
     catch (ParseException $e) {
       // Set event message if parsing the message fails.
diff --git a/tests/src/Kernel/ModeratorForwardTest.php b/tests/src/Kernel/ModeratorForwardTest.php
index fa3c87c..3da83fe 100644
--- a/tests/src/Kernel/ModeratorForwardTest.php
+++ b/tests/src/Kernel/ModeratorForwardTest.php
@@ -54,7 +54,7 @@ class ModeratorForwardTest extends KernelTestBase {
     $processor->process('unique_key', $bounce, $deliverer);
     // Message passed all tests, parsings and thus success is called.
     $this->assertSuccess($deliverer, 'unique_key');
-    $this->assertMailCount(0);
+    $this->assertMailCount(1);
 
     // Do not handle if moderator address is unset.
     /** @var \Drupal\inmail\Entity\HandlerConfig $handler_config */
@@ -64,7 +64,7 @@ class ModeratorForwardTest extends KernelTestBase {
     $deliverer = $this->createTestDeliverer();
     $processor->process('unique_key', $regular, $deliverer);
     $this->assertSuccess($deliverer, 'unique_key');
-    $this->assertMailCount(0);
+    $this->assertMailCount(2);
 
     // Do not handle, and log an error, if moderator address is same as intended
     // recipient.
@@ -74,7 +74,7 @@ class ModeratorForwardTest extends KernelTestBase {
     $deliverer = $this->createTestDeliverer();
     $processor->process('unique_key', $bounce_no_status, $deliverer);
     $this->assertSuccess($deliverer, 'unique_key');
-    $this->assertMailCount(0);
+    $this->assertMailCount(3);
 
     // Check the Past event created by the processor.
     $events = \Drupal::entityTypeManager()->getStorage('past_event')->loadMultiple();
@@ -93,7 +93,7 @@ class ModeratorForwardTest extends KernelTestBase {
     $deliverer = $this->createTestDeliverer();
     $processor->process('unique_key', $regular_x, $deliverer);
     $this->assertSuccess($deliverer, 'unique_key');
-    $this->assertMailCount(0);
+    $this->assertMailCount(4);
 
     // Again check past event log.
     $events = \Drupal::entityTypeManager()->getStorage('past_event')->loadMultiple();
@@ -107,7 +107,16 @@ class ModeratorForwardTest extends KernelTestBase {
     $deliverer = $this->createTestDeliverer();
     $processor->process('unique_key', $regular, $deliverer);
     $this->assertSuccess($deliverer, 'unique_key');
-    $this->assertMailCount(1);
+    $this->assertMailCount(6);
+
+    // Set a valid email address for this test.
+    \Drupal::configFactory()
+           ->getEditable('system.site')
+           ->set('mail', 'mail@example.com')
+           ->save();
+    $processor->process('unique_key', $regular, $deliverer);
+    $this->assertMailString('body', 'Reply', 1);
+
   }
 
   /**