--- a/src/Controller/ConferenceController.php
+++ b/src/Controller/ConferenceController.php
@@ -14,6 +14,8 @@ use Symfony\Component\HttpFoundation\File\Exception\FileException;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Messenger\MessageBusInterface;
+use Symfony\Component\Notifier\Notification\Notification;
+use Symfony\Component\Notifier\NotifierInterface;
 use Symfony\Component\Routing\Annotation\Route;
 use Symfony\Component\Workflow\Registry;
 use Twig\Environment;
@@ -60,7 +62,7 @@ class ConferenceController extends AbstractController
     /**
      * @Route("/conference/{slug}", name="conference")
      */
-    public function show(Request $request, Conference $conference, CommentRepository $commentRepository, string $photoDir)
+    public function show(Request $request, Conference $conference, CommentRepository $commentRepository, NotifierInterface $notifier, string $photoDir)
     {
         $comment = new Comment();
         $form = $this->createForm(CommentFormType::class, $comment);
@@ -90,9 +92,15 @@ class ConferenceController extends AbstractController

             $this->bus->dispatch(new CommentMessage($comment->getId(), $context));

+            $notifier->send(new Notification('Thank you for the feedback; your comment will be posted after moderation.', ['browser']));
+
             return $this->redirectToRoute('conference', ['slug' => $conference->getSlug()]);
         }

+        if ($form->isSubmitted()) {
+            $notifier->send(new Notification('Can you check your submission? There are some problems with it.', ['browser']));
+        }
+
         $offset = max(0, $request->query->getInt('offset', 0));
         $paginator = $commentRepository->getCommentPaginator($conference, $offset);

--- a/templates/conference/show.html.twig
+++ b/templates/conference/show.html.twig
@@ -3,6 +3,13 @@
 {% block title %}Conference Guestbook - {{ conference }}{% endblock %}

 {% block body %}
+    {% for message in app.flashes('notification') %}
+        <div class="alert alert-info alert-dismissible fade show">
+            {{ message }}
+            <button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">&times;</span></button>
+        </div>
+    {% endfor %}
+
     <h2 class="mb-5">
         {{ conference }} Conference
     </h2>

--- a/src/MessageHandler/CommentMessageHandler.php
+++ b/src/MessageHandler/CommentMessageHandler.php
@@ -4,14 +4,14 @@ namespace App\MessageHandler;

 use App\ImageOptimizer;
 use App\Message\CommentMessage;
+use App\Notification\CommentReviewNotification;
 use App\Repository\CommentRepository;
 use App\SpamChecker;
 use Doctrine\ORM\EntityManagerInterface;
 use Psr\Log\LoggerInterface;
-use Symfony\Bridge\Twig\Mime\NotificationEmail;
-use Symfony\Component\Mailer\MailerInterface;
 use Symfony\Component\Messenger\Handler\MessageHandlerInterface;
 use Symfony\Component\Messenger\MessageBusInterface;
+use Symfony\Component\Notifier\NotifierInterface;
 use Symfony\Component\Workflow\WorkflowInterface;

 class CommentMessageHandler implements MessageHandlerInterface
@@ -21,22 +21,20 @@ class CommentMessageHandler implements MessageHandlerInterface
     private $commentRepository;
     private $bus;
     private $workflow;
-    private $mailer;
+    private $notifier;
     private $imageOptimizer;
-    private $adminEmail;
     private $photoDir;
     private $logger;

-    public function __construct(EntityManagerInterface $entityManager, SpamChecker $spamChecker, CommentRepository $commentRepository, MessageBusInterface $bus, WorkflowInterface $commentStateMachine, MailerInterface $mailer, ImageOptimizer $imageOptimizer, string $adminEmail, string $photoDir, LoggerInterface $logger = null)
+    public function __construct(EntityManagerInterface $entityManager, SpamChecker $spamChecker, CommentRepository $commentRepository, MessageBusInterface $bus, WorkflowInterface $commentStateMachine, NotifierInterface $notifier, ImageOptimizer $imageOptimizer, string $photoDir, LoggerInterface $logger = null)
     {
         $this->entityManager = $entityManager;
         $this->spamChecker = $spamChecker;
         $this->commentRepository = $commentRepository;
         $this->bus = $bus;
         $this->workflow = $commentStateMachine;
-        $this->mailer = $mailer;
+        $this->notifier = $notifier;
         $this->imageOptimizer = $imageOptimizer;
-        $this->adminEmail = $adminEmail;
         $this->photoDir = $photoDir;
         $this->logger = $logger;
     }
@@ -62,13 +60,7 @@ class CommentMessageHandler implements MessageHandlerInterface

             $this->bus->dispatch($message);
         } elseif ($this->workflow->can($comment, 'publish') || $this->workflow->can($comment, 'publish_ham')) {
-            $this->mailer->send((new NotificationEmail())
-                ->subject('New comment posted')
-                ->htmlTemplate('emails/comment_notification.html.twig')
-                ->from($this->adminEmail)
-                ->to($this->adminEmail)
-                ->context(['comment' => $comment])
-            );
+            $this->notifier->send(new CommentReviewNotification($comment), ...$this->notifier->getAdminRecipients());
         } elseif ($this->workflow->can($comment, 'optimize')) {
             if ($comment->getPhotoFilename()) {
                 $this->imageOptimizer->resize($this->photoDir.'/'.$comment->getPhotoFilename());

--- a/config/packages/notifier.yaml
+++ b/config/packages/notifier.yaml
@@ -13,4 +13,4 @@ framework:
             medium: ['email']
             low: ['email']
         admin_recipients:
-            - { email: [email protected] }
+            - { email: "%env(string:default:default_admin_email:ADMIN_EMAIL)%" }

--- a/config/packages/notifier.yaml
+++ b/config/packages/notifier.yaml
@@ -1,7 +1,7 @@
 framework:
     notifier:
-        #chatter_transports:
-        #    slack: '%env(SLACK_DSN)%'
+        chatter_transports:
+            slack: '%env(SLACK_DSN)%'
         #    telegram: '%env(TELEGRAM_DSN)%'
         #texter_transports:
         #    twilio: '%env(TWILIO_DSN)%'

--- a/src/Notification/CommentReviewNotification.php
+++ b/src/Notification/CommentReviewNotification.php
@@ -27,4 +27,15 @@ class CommentReviewNotification extends Notification implements EmailNotificationInterface
             ->context(['comment' => $this->comment])
         );
     }
+
+    public function getChannels(Recipient $recipient): array
+    {
+        if (preg_match('{\b(great|awesome)\b}i', $this->comment->getText())) {
+            return ['email', 'chat/slack'];
+        }
+
+        $this->importance(Notification::IMPORTANCE_LOW);
+
+        return ['email'];
+    }
 }

--- a/src/Notification/CommentReviewNotification.php
+++ b/src/Notification/CommentReviewNotification.php
@@ -3,12 +3,17 @@
 namespace App\Notification;

 use App\Entity\Comment;
+use Symfony\Component\Notifier\Bridge\Slack\Block\SlackDividerBlock;
+use Symfony\Component\Notifier\Bridge\Slack\Block\SlackSectionBlock;
+use Symfony\Component\Notifier\Bridge\Slack\SlackOptions;
+use Symfony\Component\Notifier\Message\ChatMessage;
 use Symfony\Component\Notifier\Message\EmailMessage;
+use Symfony\Component\Notifier\Notification\ChatNotificationInterface;
 use Symfony\Component\Notifier\Notification\EmailNotificationInterface;
 use Symfony\Component\Notifier\Notification\Notification;
 use Symfony\Component\Notifier\Recipient\Recipient;

-class CommentReviewNotification extends Notification implements EmailNotificationInterface
+class CommentReviewNotification extends Notification implements EmailNotificationInterface, ChatNotificationInterface
 {
     private $comment;

@@ -30,6 +35,28 @@ class CommentReviewNotification extends Notification implements EmailNotificatio
         return $message;
     }

+    public function asChatMessage(Recipient $recipient, string $transport = null): ?ChatMessage
+    {
+        if ('slack' !== $transport) {
+            return null;
+        }
+
+        $message = ChatMessage::fromNotification($this, $recipient, $transport);
+        $message->subject($this->getSubject());
+        $message->options((new SlackOptions())
+            ->iconEmoji('tada')
+            ->iconUrl('https://guestbook.example.com')
+            ->username('Guestbook')
+            ->block((new SlackSectionBlock())->text($this->getSubject()))
+            ->block(new SlackDividerBlock())
+            ->block((new SlackSectionBlock())
+                ->text(sprintf('%s (%s) says: %s', $this->comment->getAuthor(), $this->comment->getEmail(), $this->comment->getText()))
+            )
+        );
+
+        return $message;
+    }
+
     public function getChannels(Recipient $recipient): array
     {
         if (preg_match('{\b(great|awesome)\b}i', $this->comment->getText())) {

--- a/src/Notification/CommentReviewNotification.php
+++ b/src/Notification/CommentReviewNotification.php
@@ -3,6 +3,7 @@
 namespace App\Notification;

 use App\Entity\Comment;
+use Symfony\Component\Notifier\Bridge\Slack\Block\SlackActionsBlock;
 use Symfony\Component\Notifier\Bridge\Slack\Block\SlackDividerBlock;
 use Symfony\Component\Notifier\Bridge\Slack\Block\SlackSectionBlock;
 use Symfony\Component\Notifier\Bridge\Slack\SlackOptions;
@@ -16,10 +17,12 @@ use Symfony\Component\Notifier\Recipient\Recipient;
 class CommentReviewNotification extends Notification implements EmailNotificationInterface, ChatNotificationInterface
 {
     private $comment;
+    private $reviewUrl;

-    public function __construct(Comment $comment)
+    public function __construct(Comment $comment, string $reviewUrl)
     {
         $this->comment = $comment;
+        $this->reviewUrl = $reviewUrl;

         parent::__construct('New comment posted');
     }
@@ -52,6 +55,10 @@ class CommentReviewNotification extends Notification implements EmailNotificatio
             ->block((new SlackSectionBlock())
                 ->text(sprintf('%s (%s) says: %s', $this->comment->getAuthor(), $this->comment->getEmail(), $this->comment->getText()))
             )
+            ->block((new SlackActionsBlock())
+                ->button('Accept', $this->reviewUrl, 'primary')
+                ->button('Reject', $this->reviewUrl.'?reject=1', 'danger')
+            )
         );

     return $message;

--- a/src/MessageHandler/CommentMessageHandler.php
+++ b/src/MessageHandler/CommentMessageHandler.php
@@ -60,7 +60,8 @@ class CommentMessageHandler implements MessageHandlerInterface

             $this->bus->dispatch($message);
         } elseif ($this->workflow->can($comment, 'publish') || $this->workflow->can($comment, 'publish_ham')) {
-            $this->notifier->send(new CommentReviewNotification($comment), ...$this->notifier->getAdminRecipients());
+            $notification = new CommentReviewNotification($comment, $message->getReviewUrl());
+            $this->notifier->send($notification, ...$this->notifier->getAdminRecipients());
         } elseif ($this->workflow->can($comment, 'optimize')) {
             if ($comment->getPhotoFilename()) {
                 $this->imageOptimizer->resize($this->photoDir.'/'.$comment->getPhotoFilename());

--- a/src/Message/CommentMessage.php
+++ b/src/Message/CommentMessage.php
@@ -5,14 +5,21 @@ namespace App\Message;
 class CommentMessage
 {
     private $id;
+    private $reviewUrl;
     private $context;

-    public function __construct(int $id, array $context = [])
+    public function __construct(int $id, string $reviewUrl, array $context = [])
     {
         $this->id = $id;
+        $this->reviewUrl = $reviewUrl;
         $this->context = $context;
     }

+    public function getReviewUrl(): string
+    {
+        return $this->reviewUrl;
+    }
+
     public function getId(): int
     {
         return $this->id;

--- a/src/Controller/AdminController.php
+++ b/src/Controller/AdminController.php
@@ -12,6 +12,7 @@ use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\KernelInterface;
 use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Routing\Annotation\Route;
+use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
 use Symfony\Component\Workflow\Registry;
 use Twig\Environment;

@@ -51,7 +52,8 @@ class AdminController extends AbstractController
         $this->entityManager->flush();

         if ($accepted) {
-            $this->bus->dispatch(new CommentMessage($comment->getId()));
+            $reviewUrl = $this->generateUrl('review_comment', ['id' => $comment->getId()], UrlGeneratorInterface::ABSOLUTE_URL);
+            $this->bus->dispatch(new CommentMessage($comment->getId(), $reviewUrl));
         }

         return $this->render('admin/review.html.twig', [
--- a/src/Controller/ConferenceController.php
+++ b/src/Controller/ConferenceController.php
@@ -17,6 +17,7 @@ use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Notifier\Notification\Notification;
 use Symfony\Component\Notifier\NotifierInterface;
 use Symfony\Component\Routing\Annotation\Route;
+use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
 use Twig\Environment;

 class ConferenceController extends AbstractController
@@ -89,7 +90,8 @@ class ConferenceController extends AbstractController
                 'permalink' => $request->getUri(),
             ];

-            $this->bus->dispatch(new CommentMessage($comment->getId(), $context));
+            $reviewUrl = $this->generateUrl('review_comment', ['id' => $comment->getId()], UrlGeneratorInterface::ABSOLUTE_URL);
+            $this->bus->dispatch(new CommentMessage($comment->getId(), $reviewUrl, $context));

             $notifier->send(new Notification('Thank you for the feedback; your comment will be posted after moderation.', ['browser']));

--- a/config/packages/messenger.yaml
+++ b/config/packages/messenger.yaml
@@ -20,3 +20,5 @@ framework:
             # Route your messages to the transports
             App\Message\CommentMessage: async
             Symfony\Component\Mailer\Messenger\SendEmailMessage: async
+            Symfony\Component\Notifier\Message\ChatMessage: async
+            Symfony\Component\Notifier\Message\SmsMessage: async