Webhook

The Webhook block sends HTTP POST requests to external webhook endpoints with automatic webhook headers and optional HMAC signing.

Configuration

The destination endpoint for your webhook request. Supports both static URLs and dynamic values from other blocks.

JSON data to send in the request body. Use the AI wand to generate payloads or reference workflow variables:

{
  "event": "workflow.completed",
  "data": {
    "result": "<agent.content>",
    "timestamp": "<function.result>"
  }
}

Optional secret for HMAC-SHA256 payload signing. When provided, adds an X-Webhook-Signature header:

X-Webhook-Signature: t=1704067200000,v1=5d41402abc4b2a76b9719d911017c592...

To verify signatures, compute HMAC-SHA256(secret, "${timestamp}.${body}") and compare with the v1 value.

Custom key-value headers to include with the request. These override any automatic headers with the same name.

Every request includes these headers automatically:

Header	Description
`Content-Type`	`application/json`
`X-Webhook-Timestamp`	Unix timestamp in milliseconds
`X-Delivery-ID`	Unique UUID for this delivery
`Idempotency-Key`	Same as `X-Delivery-ID` for deduplication

Output	Type	Description
`data`	json	Response body from the endpoint
`status`	number	HTTP status code
`headers`	object	Response headers

Notify external services - Send workflow results to Slack, Discord, or custom endpoints

Agent → Function (format) → Webhook (notify)

Trigger external workflows - Start processes in other systems when conditions are met

Condition (check) → Webhook (trigger) → Response

The Webhook block always uses POST. For other HTTP methods or more control, use the API block.