Trigger on Webhook

Trigger on Webhook node

Node Description

Trigger on Webhook is a trigger node that serves as the entry point of a scenario. When a request is sent to the node's URL, the scenario starts executing.

Node Configuration

After adding the Trigger on Webhook node, two URL versions are automatically generated and displayed in the Path field:

Production URL — requests can be sent continuously; the scenario keeps running until manually stopped or a critical error occurs.
Development URL — the scenario runs once after a single request, then stops. Use this for testing and debugging.

Production and Development URLs

The generated URL can be partially modified (1) or copied (2) for use in requests.

URL modification and copy controls

You can send requests to the Trigger on Webhook node using the POST method (to transmit data) or the GET method (to trigger the scenario without a body).

Webhook Response Modes

The platform can reply to a webhook request in three ways:

Default response (200 OK) — if your scenario has no Webhook Response node, the platform returns 200 OK.
Custom response — add a Webhook Response node to return a custom body, status code, and headers.
Instant reply (fast mode) — if the sender expects an immediate response (for example, due to a short timeout), use fast mode via URL parameters. See Fast mode below.

Fast mode (instant webhook reply)

Fast mode lets you return an instant reply using webhook URL query parameters. This is useful when the sender expects a response very quickly and may close the connection before the scenario finishes.

`__ln.fast=1` — Fast Mode

When __ln.fast=1 is set, the webhook returns a response immediately, before the scenario completes. In this mode, the Webhook Response node is not used for the webhook reply (it won’t run), because the response has already been sent to the sender.

Important

In fast mode, the client sending the request may not see scenario errors, for example if the scenario is inactive and so on.
If the webhook for requests with the __ln.fast=1 parameter is not found, the platform will still return 200 OK.

Postman request URL with __ln.fast=1 highlighted

Available `__ln.*` parameters

Postman request with __ln.resp.* parameters and a 201 Created response

Parameter	What it does	Example
`__ln.fast`	Enables fast mode: Latenode replies immediately, before the scenario runs.	`__ln.fast=1`
`__ln.resp.body`	Response body for async replies (no Webhook Response node, or `__ln.fast=1` enabled).	`__ln.resp.body=Hello%20World`
`__ln.resp.status`	HTTP status code for async replies.	`__ln.resp.status=201`
`__ln.resp.header.<header>`	Response header for async replies.	`__ln.resp.header.content-type=application/json`

Full URL Example

https://<your-webhook-url>?__ln.fast=1&__ln.resp.body=Hello%20World&__ln.resp.status=201&__ln.resp.header.content-type=application/json

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