Webhook Trigger

Webhook Trigger gives a workflow a public URL. An incoming HTTP request starts a run and makes the request data available to later steps.

Webhook Trigger is provided by GC API Alchemist. Flowcrafter advertises it in the step picker when API Alchemist is inactive; installing and activating API Alchemist unlocks the trigger.

When to use it

Use it when you need a payment service, CRM, another website, or an automation tool to start a workflow.

Settings

Setting	What it controls
Webhook URL	Generated after the workflow is saved. Copy this URL into the sending service.
Allowed methods	Accept Any method (default), or only POST, GET, or PUT.

Use Listen for webhook during testing to capture a real request and expose its fields in the flow tag picker.

Output and branch

The single default branch receives:

Output	Meaning
method	HTTP method used by the sender.
headers	Request headers.
body	A parsed object for JSON, otherwise the raw body text.
query_params	URL query parameters.
ip	Sender IP address.
run_started_at, run_started_timestamp	When this run started, in site time and as a Unix timestamp.
last_completed_run_started_at, last_completed_run_started_timestamp	When the last run that completed successfully started. Empty until a run has completed.

Every trigger carries the two run-start values. To fetch only what’s new since the last run, put Last completed run started in Get Entries’ Created after and This run started in its Created before.

Security and known limitations

• Production requests run only the saved, active, valid workflow. Test listening can use the frozen test workflow.
• The random URL token is the core access check. Treat the URL like a password; core does not verify provider signatures.
• Requests larger than the site’s maximum upload size are rejected.
• Provider retries are deduplicated by a supported delivery header, or by the raw body when no delivery ID is sent.
• A disallowed method returns an error instead of starting a run.

Example

For a payment callback:

1. Set Allowed methods to POST.
2. Have the provider send JSON such as {"entry_id":42,"status":"paid"}.
3. Use Condition (data) to compare the webhook body’s status with paid before updating entry 42.