MailInApp for Claude Desktop

Connects Claude Desktop to your MailInApp account, so you can design, send, and read the results of interactive emails — polls, quizzes, countdowns, forms, product checkout, and more — right from a chat with Claude.

This is the desktop-extension version of the MailInApp connector. If you'd rather not install anything locally, you can add MailInApp as a custom connector directly in Claude.ai or Claude Desktop's Settings → Connectors instead, using https://mailinapp.com/api/mcp — this extension just saves you that step.

Install

1. Download the latest .mcpb file from this repo's Releases.
2. In Claude Desktop: Settings → Extensions → Install Extension, and pick the downloaded file.
3. Claude Desktop will ask you to confirm before running the extension's local code — this is standard for any side-loaded (non-directory) extension.
4. The first time Claude actually calls a MailInApp tool, your browser opens to MailInApp's own sign-in and consent screen, where you choose which permissions to grant. Nothing connects until you approve that screen.

What it can and can't do

Once connected, Claude can read and edit your MailInApp projects, check campaign results, and manage contacts — scoped to exactly the permissions you approved on the consent screen. Sending a real campaign always requires an extra explicit confirmation step, showing you the recipient count and a rendered preview first, so a chat message alone can never trigger a real send. See Scopes & permissions for the full breakdown, and Security for how to review or revoke access at any time from your MailInApp account.

How it works

This extension contains no MailInApp-specific server code. It's a small bridge (server/index.js) that runs mcp-remote, an open-source tool that lets Claude Desktop talk to a remote server over the Model Context Protocol — the same remote server every MailInApp connector uses, whether you connect through this extension, Claude.ai, ChatGPT, or Gemini. Nothing about what Claude can do differs based on which of those you use; this just runs the bridge on your own machine instead of MailInApp's.

Your MailInApp login and permissions never pass through this extension's code — the OAuth sign-in happens directly in your browser against mailinapp.com, and the resulting access token is stored locally on your machine by mcp-remote, not by us.

Building from source

npm install
npx @anthropic-ai/mcpb pack . mailinapp.mcpb

npm install vendors mcp-remote locally so the extension works offline after the first launch. Feel free to inspect server/index.js — it's under 40 lines — before installing, if you'd rather verify what's running yourself than take our word for it.

Links

• Documentation
• Privacy policy
• Terms
• Support: support@mailinapp.com