JMAP MCP
A Model Context Protocol (MCP) server that provides tools for interacting with JMAP (JSON Meta Application Protocol) email servers. Built with Deno and using the jmap-jam client library.
What is JMAP MCP?
JMAP MCP is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to model context protocol (mcp) server that provides tools for interacting with jmap (json meta application protocol) email servers. built with deno and using the jmap-jam client library.
A Model Context Protocol (MCP) server that provides tools for interacting with JMAP (JSON Meta Application Protocol) email servers. Built with Deno and using the jmap-jam client library.
This server falls under the Communication category on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- A Model Context Protocol (MCP) server that provides tools fo
Use Cases
Maintainer
Works with
Installation
Manual Installation
npx jmapConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use JMAP MCP
The JMAP MCP server gives AI assistants full access to JMAP-compliant email servers such as Fastmail, Cyrus IMAP, and Stalwart Mail Server, implementing RFC 8620 and RFC 8621 via the jmap-jam client library. It exposes tools for searching, reading, composing, replying to, moving, and deleting emails, as well as listing mailbox folders and performing state-based incremental sync. Built with Deno and TypeScript, it enables AI agents to act as capable email clients without requiring traditional IMAP/SMTP integrations.
Prerequisites
- Deno v1.40 or later installed (https://deno.land)
- A JMAP-compatible email provider account (e.g. Fastmail, Cyrus IMAP, Stalwart)
- A JMAP bearer token or API key from your email provider
- The JMAP session URL for your provider (e.g. https://api.fastmail.com/jmap/session)
- An MCP-compatible client such as Claude Desktop or Claude Code
Obtain your JMAP bearer token
Log in to your email provider and generate an API token with IMAP/JMAP access. For Fastmail, go to Settings → Privacy & Security → API Tokens and create a token with mail access.
Identify your JMAP session URL
The session URL is typically the well-known JMAP endpoint for your provider. For Fastmail it is `https://api.fastmail.com/jmap/session`; for self-hosted Stalwart it is usually `https://mail.yourdomain.com/.well-known/jmap`.
Add the server to your MCP client configuration
Add a JMAP entry to your MCP client config. The server runs via Deno and fetches its code from JSR (the JavaScript Registry). Set the required environment variables in the `env` block.
Install via Claude Code marketplace (alternative)
If you use Claude Code, you can install the JMAP MCP plugin directly from the marketplace.
/plugin marketplace add wyattjoh/claude-code-marketplace
/plugin install jmap-mcp@wyattjoh-marketplaceVerify by listing your mailboxes
Ask your AI client to list your mailboxes or search for recent emails to confirm the connection is working.
JMAP MCP Examples
Client configuration
Claude Desktop config block using Deno to run the JMAP MCP server from JSR with Fastmail credentials.
{
"mcpServers": {
"jmap": {
"type": "stdio",
"command": "deno",
"args": [
"run",
"--allow-net=api.fastmail.com",
"--allow-env=JMAP_SESSION_URL,JMAP_BEARER_TOKEN,JMAP_ACCOUNT_ID",
"jsr:@wyattjoh/[email protected]"
],
"env": {
"JMAP_SESSION_URL": "https://api.fastmail.com/jmap/session",
"JMAP_BEARER_TOKEN": "YOUR_FASTMAIL_API_TOKEN"
}
}
}
}Prompts to try
Example email management tasks you can ask once the server is connected.
- "List all unread emails in my inbox"
- "Search for emails from [email protected] in the last 7 days"
- "Reply to the latest email from Alice with a confirmation that I will attend the meeting"
- "Move all emails from [email protected] to the Newsletters folder"
- "Compose a new email to [email protected] with subject 'Project Update' and summarise the key points from my notes"Troubleshooting JMAP MCP
Deno permission denied errors when starting the server
Ensure the `--allow-net` flag includes your JMAP server's hostname and that `--allow-env` lists `JMAP_SESSION_URL`, `JMAP_BEARER_TOKEN`, and `JMAP_ACCOUNT_ID`. If you use a non-Fastmail provider, update the `--allow-net` domain to match your server.
Authentication fails with 401 Unauthorized
Verify the bearer token is correct and has not expired. For Fastmail, regenerate an API token under Settings → Privacy & Security → API Tokens and ensure it has JMAP/mail access permissions.
JMAP_ACCOUNT_ID is required but not set
The account ID is auto-detected from the session URL in most cases. If auto-detection fails, find your account ID in your email provider's developer settings or API documentation and set `JMAP_ACCOUNT_ID` in your config's `env` block.
Frequently Asked Questions about JMAP MCP
What is JMAP MCP?
JMAP MCP is a Model Context Protocol (MCP) server that model context protocol (mcp) server that provides tools for interacting with jmap (json meta application protocol) email servers. built with deno and using the jmap-jam client library. It connects AI assistants to external tools and data sources through a standardized interface.
How do I install JMAP MCP?
Follow the installation instructions on the JMAP MCP GitHub repository. Clone the repo, install dependencies, and add the server config to your AI client.
Which AI clients work with JMAP MCP?
JMAP MCP works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is JMAP MCP free to use?
Yes, JMAP MCP is open source and available under the MIT license. You can use it freely in both personal and commercial projects.
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