Outbound Webhooks¶

Any HTTP mock can fire a templated outbound HTTP callback when it's matched — simulating systems that notify clients asynchronously via server-initiated requests (payment gateway callbacks, job-completion notifications, message broker pushes, etc.) rather than only responding synchronously.

Dispatch is fire-and-forget: the callback is sent in the background and never blocks or delays the mock's own HTTP response. url, headers, and body all support the same Go template syntax as response bodies, so the callback target and payload can be derived from the triggering request (e.g. a caller-supplied callback_url field).

      - id: create-payment
        request:
          method: POST
          path: /v1/payment
        response:
          status: 201
          body: '{"paymentId":"pay_123"}'
        webhooks:
          - url: "{{.request.body.webhookUrl}}"
            method: POST
            headers:
              Authorization: "{{.request.body.webhookSecret}}"
            delay: 300ms        # wait before sending, simulating async processing
            retries: 2          # additional attempts on failure or a 5xx response
            retry_delay: 1s
            body: |
              {"event": "payment.created", "id": "{{uuid}}"}

Every attempt (including retries) is recorded and available via the management API:

curl http://localhost:9091/api/webhooks                 # attempt history
curl -X DELETE http://localhost:9091/api/webhooks        # clear history
curl -X POST http://localhost:9091/api/webhooks/send \
  -d '{"url":"https://example.com/hook","body":"{\"ping\":true}"}'  # send one ad hoc

See the Nets/Nexi preset for a full example that templates the callback URL and authorization straight out of the request body, matching how real payment gateways accept a webhooks array.

Outbound Webhooks¶

See also¶