Substack MCP: What the Official Server Can Do, and Running a Newsletter From Claude Instead

Short answer: Substack has an official MCP server, but you probably can't use it, and it can't post for you. It's read-only and only open to admins of Bestseller publications, which have at least hundreds of paid subscribers. There's still no public Substack API for writing or sending posts. Community MCP servers that do post use your browser login cookie and Substack's private endpoints, which carries real risks.

If what you want is to write, schedule and send your newsletter from Claude or ChatGPT, you'll need a platform built for it. This guide covers every Substack option first, as of October 2026.

We run Audienceful, a newsletter platform with its own MCP server, and many of our customers came from Substack, so weigh our view accordingly.

The official Substack MCP server

Substack added an MCP server in mid-2026, hosted at https://mcp.substack.com/api/v1/mcp. You add it to Claude, ChatGPT or Cursor as a custom connector and sign in.

Who can use it: you must be an admin of the publication, and the publication must be a Bestseller. Substack awards that badge on paid subscribers alone, starting in the hundreds. Free trials and comps don't count. If your publication isn't eligible, you'll see an error when you connect.

What it can do: in Substack's words, it has "read-only access to publication data such as dashboard metrics, traffic data, and publication settings." That's useful for questions like "where did last month's new subscribers come from?"

What it can't do: Substack is clear that it "cannot publish posts, send Notes, or modify your account." It also can't see your profile or Notes activity.

Is there a Substack API?

Not one you can use to publish or send. Substack's developer API is limited to approved partners and public profile data, which "does not include private, restricted, or inferred information." Neither the API nor the MCP server can create a post or email your subscribers.

Community Substack MCP servers

Several open-source projects fill the gap. They fall into two groups:

• Read-only servers that parse public posts or your feed. They're low risk and limited.
• Read-write servers that log in as you with your Substack session cookie and call Substack's undocumented internal endpoints. The most complete ones can create drafts, post Notes and, in at least one case, publish a post and email it to your subscribers.

Before you hand one your cookie:

• It's full account access. A session cookie can do anything you can. One project's README puts it plainly: "Treat the session token exactly like a password."
• It can break any day. Private endpoints change without notice, sessions expire, and some of these projects have already disappeared from GitHub.
• It may break Substack's terms, which restrict automated access to the service.
• Mistakes are permanent. As another README warns, "an email cannot be recalled."

How to run a newsletter from Claude instead

If you want an assistant to actually run your newsletter, use a platform with an official MCP server that can write and send. With Audienceful, you connect once (Claude, ChatGPT, Gemini, Cursor or Claude Code all work) and your assistant can:

• Draft this week's issue from your notes or a link, in an editor you and your co-writers can edit together.
• Send you a test, then schedule it for Tuesday at 9am. Before anything goes to subscribers, it must show you the recipients and timing, and your approval works once, for exactly those people.
• Build the welcome sequence new subscribers get, created paused so you can check it.
• Report back on opens, clicks and which links readers liked.

Every issue also becomes a page in your newsletter archive, so your back catalog still lives on the web. If you'd rather not use an outside assistant, the AI agent built into Audienceful does the same work in the app. The MCP server is included on every plan, including Free.

Switching from Substack?

• An assistant that can publish. Draft, test, schedule and send your issue from Claude or ChatGPT, with your approval, on an official, supported server.
• No revenue cut. Substack takes 10% of paid subscription revenue. Audienceful charges a flat price by contacts. See the full Substack comparison.
• Your domain and your design. Send from your own domain, with themes you control and a web archive of every issue.
• Room to grow. Segments, welcome sequences and automations for when a single broadcast list isn't enough.

Start free: the free plan covers up to 1,000 contacts. Then bring your list over with our email list import guide.

Moving from Substack

Substack makes leaving fairly easy:

1. Export everything: in Substack, go to Settings → Exports and create a new export. You'll get a zip with your posts, subscriber list and stats.
2. Or export just subscribers: on the Subscribers page, open the menu and choose Export to download a CSV.
3. Import into Audienceful: follow the email list import guide or our migration guide.

For a wider view, see Substack vs Audienceful, the best Substack alternatives and email marketing for newsletter creators.

FAQs

Does Substack have an MCP server?

Yes, since mid-2026. It's read-only and available only to admins of Bestseller publications. It can read metrics, traffic and settings, but can't publish or send.

Can I connect Substack to Claude?

If your publication is a Bestseller, you can add Substack's MCP server to Claude as a custom connector for read-only analytics. To write and send from Claude, you'd need an unofficial server that uses your login cookie, or a different newsletter platform.

Does Substack have a public API?

Not for publishing or sending. Substack's developer API covers approved partners and public profile data only.

What's the best Substack MCP alternative?

If you want an assistant that can write, schedule and send your newsletter with your approval, Audienceful's email marketing MCP server works with Claude, ChatGPT, Gemini and Cursor, and it's included on every plan.