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Node ReferenceWebhook Call Node
Node Reference

Webhook Call Node

Make outbound HTTP requests to external APIs.

The Webhook Call node sends an outbound HTTP request to an external service from inside a workflow. You configure a URL, method, and optional headers; the request body comes from the connected upstream node. The response body is exposed for downstream nodes, with the HTTP status surfaced on the node.

Outbound request vs inbound trigger
Use the Webhook Call node to call an external API. Use the Webhook Trigger node when an external system needs to start a workflow by calling Builder Studio.

Ports

PortDirectionTypePurpose
body-inInputtextRequest body sent with the call. Optional.
response-outOutputtextThe response body returned by the called service.

Configure the call

  1. Set the URL

    Enter an absolute http:// or https:// URL. The node validates the URL as you type. URLs with embedded credentials (user:pass@) or non-HTTP protocols are rejected, and the URL must be present before the call can run.

  2. Pick the method

    Choose GET, POST, PUT, PATCH, or DELETE. The default is POST.

  3. Add headers (optional)

    Provide headers as a JSON object. The editor validates the JSON and the header names as you type, so an invalid entry is flagged before you send.

  4. Connect a body and run

    Wire an upstream node into body-in if the request needs a body, then send the request. While calling, the node shows a Calling status; on completion it shows the status code and a preview of the response.

Headers (JSON object)json
{  "Authorization": "Bearer <token>",  "X-Custom-Header": "value"}

Header rules

Headers must be a flat JSON object of string values. Builder Studio enforces a few limits so the outbound proxy stays well-behaved:

  • At most 64 header entries.
  • Header names must be valid HTTP token characters, and values cannot contain line breaks.
  • Hop-by-hop and host-controlled headers are blocked, including host, connection, content-length, cookie, x-forwarded-*, and proxy-authorization.

Response handling

  • The request is sent through the server-side webhook relay rather than directly from the browser, and is subject to a 30-second timeout.
  • The response body is returned on response-out. The node also records the HTTP status code, shown as a colored badge by status class.
  • Responses are capped at 5 MB. A larger response fails with a size-limit error rather than buffering unbounded data.
  • A non-2xx status from the relay, or an unparseable response, surfaces as a node error you can dismiss and retry.
Server configuration required
Outbound webhook calls run through a proxy that must be configured by the deployment operator. If the proxy is not configured, the call fails with a configuration error instead of sending the request.
Related
Pair this node with Webhook Trigger to build request/response flows, and see Integrations for managed connections to specific providers.

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