Extraction step

API call

The api_call step performs an HTTP request from inside the live page, so it carries the session's cookies — often faster and more robust than driving the UI, especially against endpoints discovered from the site's own network traffic.

In a workflow, this is a step object with "type": "api_call". Steps run in order, and each step can read the outputs of the steps before it. See the full workflows reference for the 30+ step types.

Writ runs on your own accounts, with your own credentials and data, on sites you are authorized to use.

Fields

Field	Type	Description
`url` required	`string`	The endpoint URL (placeholders supported).
`method`	`string`	GET, POST, PUT, PATCH, or DELETE.
`headers`	`map`	Request headers; reference `{{vault:name}}` secrets, never inline them.
`body`	`json`	Request body for write methods; `{{extracted:key}}` values from earlier steps resolve here.

Example

A single api_call step as it appears in a workflow's steps array:

{
  "type": "api_call",
  "config": {
    "method": "GET",
    "url": "https://example.com/api/products?page={{page}}",
    "headers": { "Authorization": "Bearer {{vault:api_token}}" }
  }
}

How it behaves

Runs as an in-page request, so the logged-in session from earlier steps is reused.
Response values can be named and chained into later steps as {{extracted:key}}.
Only call endpoints on services you are authorized to use.

Where it runs

The api_call step executes wherever the run executes. On your local or BYO agent there is no compute charge and the agent can reach intranet-only systems; on Writ cloud the run is metered by running time (~$0.12 per browser-hour, from your plan’s included usage wallet.

Related steps

login_post: Sign in as a request instead of a DOM form, on your own account.
evaluate: Run JavaScript in the page and capture its result.
extract: Pull structured data out of the page into named fields.

What next

Workflows - the full step vocabulary and the workflow object.
Recorder - capture steps by clicking through a site.
Managed endpoints - turn the workflow into a REST endpoint, or an MCP tool.