Feature: #99629 - Webhooks - Outgoing webhooks for TYPO3

See forge#99629


A webhook is an automated message sent from one application to another via HTTP.

This feature adds the possibility to configure webhooks in TYPO3.

A new backend module System > Webhooks provides the possibility to configure webhooks. The module is available in the TYPO3 backend for users with administrative rights.

A webhook is defined as an authorized POST or GET request to a defined URL. For example, a webhook can be used to send a notification to a Slack channel when a new page is created in TYPO3.

Any webhook record is defined by a universally unique identifier (UUID), a speaking name, an optional description, a trigger, the target URL and a signing-secret. Both the unique identifier and the signing-secret are generated in the backend when a new webhook is created.

Triggers provided by the TYPO3 Core

The TYPO3 Core currently provides the following triggers for webhooks:

  • Page Modification: Triggers when a page is created, updated or deleted
  • File Added: Triggers when a file is added
  • File Updated: Triggers when a file is updated
  • File Removed: Triggers when a file is removed
  • Login Error Occurred: Triggers when a login error occurred
  • Redirect Was Hit: Triggers when a redirect has been hit

These triggers are meant as a first set of triggers that can be used to send webhooks, further triggers will be added in the future. In most projects however, it is likely that custom triggers are required.

Custom triggers

Trigger by PSR-14 events

Custom triggers can be added by creating a Message for an specific PSR-14 event and tagging that message as a webhook message.

The following example shows how to create a simple webhook message for the \TYPO3\CMS\Core\Resource\Event\AfterFolderAddedEvent:

namespace TYPO3\CMS\Webhooks\Message;

use TYPO3\CMS\Core\Attribute\WebhookMessage;
use TYPO3\CMS\Core\Messaging\WebhookMessageInterface;
use TYPO3\CMS\Core\Resource\Event\AfterFolderAddedEvent;

    identifier: 'typo3/folder-added',
    description: 'LLL:EXT:webhooks/Resources/Private/Language/locallang_db.xlf:sys_webhook.webhook_type.typo3-folder-added'
final class FolderAddedMessage implements WebhookMessageInterface
    public function __construct(
        private readonly int $storageUid,
        private readonly string $identifier,
        private readonly string $publicUrl
    ) {

    public static function createFromEvent(AfterFolderAddedEvent $event): self
        $file = $event->getFile();
        return new self($file->getStorage()->getUid(), $file->getIdentifier(), $file->getPublicUrl());

    public function jsonSerialize(): array
        return [
            'storage' => $this->storageUid,
            'identifier' => $this->identifier,
            'url' => $this->publicUrl,
  1. Create a final class implementing \TYPO3\CMS\Core\Messaging\WebhookMessageInterface.
  2. Add the \TYPO3\CMS\Core\Attribute\WebhookMessage attribute to the class. The attribute requires the following information:

    • identifier: The identifier of the webhook message.
    • description: The description of the webhook message. This description is used to describe the trigger in the TYPO3 backend.
  3. Add a static method createFromEvent() that creates a new instance of the message from the event you want to use as a trigger.
  4. Add a method jsonSerialize() that returns an array with the data that should be sent with the webhook.

Trigger by hooks or custom code

In case a trigger is not provided by the TYPO3 Core or a PSR-14 event is not available, it is possible to create a custom trigger - for example by using a TYPO3 hook.

The message itself should look similar to the example above, but does not need the createFromEvent() method.

Instead, the custom code (hook implementation) will create the message and dispatch it.

Example hook implementation for a DataHandler hook (see \TYPO3\CMS\Webhooks\Listener\PageModificationListener):

public function __construct(
    protected readonly \Symfony\Component\Messenger\MessageBusInterface $bus
) {

public function processDatamap_afterDatabaseOperations($status, $table, $id, $fieldArray, DataHandler $dataHandler)
    if ($table !== 'pages') {
    // ...
    $message = new PageModificationMessage(
    // ...

Use Services.yaml instead of the PHP attribute

Instead of the PHP attribute the Services.yaml can be used to define the webhook message. The following example shows how to define the webhook message from the example above in the Services.yaml:

      - name: 'core.webhook_message'
        identifier: 'typo3/folder-added'
        description: 'LLL:EXT:webhooks/Resources/Private/Language/locallang_db.xlf:sys_webhook.webhook_type.typo3-folder-added'

HTTP headers of every webhook

With every webhook request, the following HTTP headers are sent:

  • Content-Type: application/json
  • Webhook-Signature-Algo: sha256
  • Webhook-Signature: <hash>

The hash is calculated with the secret of the webhook and the JSON encoded data of the request. The hash is created with the PHP function hash_hmac. See the following section about the hash calculation.

Hash calculation

The hash is calculated with the following PHP code:

$hash = hash_hmac('sha256', sprintf(
    $identifier, // The identifier of the webhook (uuid)
    $body // The JSON encoded body of the request
), $secret); // The secret of the webhook

The hash is sent as HTTP header Webhook-Signature and should be used to validate that the request was sent from the TYPO3 instance and has not been manipulated. To verify this on the receiving end, build the hash with the same algorithm and secret and compare it with the hash that was sent with the request.

The hash is not meant to be used as a security mechanism, but as a way to verify that the request was sent from the TYPO3 instance.

Technical background and advanced usage

The webhook system is based on the Symfony Messenger component. The messages are simple PHP objects that implement an interface that denotes them as webhook messages.

That message is then dispatched to the Symfony Messenger bus. The TYPO3 Core provides a \TYPO3\CMS\Webhooks\MessageHandler\WebhookMessageHandler that is responsible for sending the webhook requests to the third-party system, if configured to do so. The handler looks up the webhook configuration and sends the request to the configured URL.

Messages are sent to the bus in any case. The handler is then responsible for checking whether or not an external request (webhook) should be sent.

If advanced request handling is necessary or a custom implementation should be used, a custom handler can be created that handles WebhookMessageInterface messages.


The TYPO3 Core now provides a convenient GUI to create and send webhooks to third-party systems. In combination with the system extension reactions TYPO3 can now be used as a low-code/no-code integration platform between multiple systems.