Is Substack have API for posting?

Yes — unofficial. API Substack lets authors draft, publish, and schedule posts. Register to get an API key.

Short answer

Yes — but Substack does not offer an official public posting API for authors. Authors still post through the Substack editor and session-based flows.

What API Substack provides

API Substack is an unofficial posting API for Substack authors. It helps you draft, publish, and schedule posts programmatically without living in the browser editor.

You can use it as REST API calls, a Python client, a CLI, or an MCP server for AI tools such as Cursor, Claude, and ChatGPT-style workflows.

How it works

1) Create an account on API Substack. 2) Generate an API key after you sign in. 3) Attach your Substack publication. 4) Send draft / publish / schedule requests through the API, CLI, or MCP.

Registration is required. Without an account and API key you cannot call the posting endpoints.

What you can do

Create drafts, update drafts, publish now, schedule releases, and work with tags — from code, automation tools (Make.com, n8n, Zapier), or AI clients via MCP.