mailbox-mcp

Give your AI tools access to your email. Search, read, send, and manage messages across multiple accounts without leaving your terminal.

mailbox-mcp is an MCP server that connects your email to Claude Code, Cursor, Windsurf, or any AI tool that supports the Model Context Protocol. Instead of switching between your terminal and Gmail, you ask the AI to find that invoice, summarize a thread, or draft a reply — and it does.

What makes this different from the 60+ other email MCP servers:

• Multiple accounts, one server. Work email, personal email, client accounts — all accessible through a single server. No need to run separate instances.
• Not just Gmail. Supports Gmail (full API), any IMAP/SMTP provider (ProtonMail, corporate mail, self-hosted), and JMAP (Fastmail, Stalwart, Topicbox). Add providers without changing a line of tool code.
• Security-conscious. Encrypted credentials (AES-256-GCM), prompt injection fencing on email content, rate limiting, TLS enforcement, SSRF protection with IP encoding evasion detection, input validation.
• Tools for the workflows that matter. Search, read, send, reply, forward, drafts, labels, filters, templates, signatures, vacation replies, attachments, unsubscribe, and more.
• Zero native dependencies. Pure Node.js. Install and run anywhere.

Quick Start

Install

Add to your Claude Code MCP config (~/.claude.json). The package runs straight from npm via npx:

{
  "mcpServers": {
    "mailbox": {
      "command": "npx",
      "args": ["-y", "mailbox-mcp"],
      "env": {
        "MAILBOX_MCP_PASSPHRASE": "a-long-random-passphrase"
      }
    }
  }
}

MAILBOX_MCP_PASSPHRASE is the passphrase used to encrypt IMAP/JMAP credentials at rest; it's required before adding an IMAP or JMAP account, and unused for Gmail-only setups.

git clone https://github.com/jgalea/mailbox-mcp.git
cd mailbox-mcp
npm install && npm run build

Add a Gmail Account

1. Create a Google Cloud project

1. Go to Google Cloud Console and create a new project
2. Enable the Gmail API: APIs & Services > Library > Gmail API > Enable

2. Set up OAuth consent screen

1. Go to Google Auth Platform > Branding
2. Set App name and User support email
3. Go to Audience, select External
4. Add the Google account you'll sign in with as a test user (this must be the exact @gmail.com address you use to authenticate, not a workspace alias)

3. Create OAuth credentials

1. Go to Google Auth Platform > Clients > Create Client
2. Application type: Desktop app
3. Click Create
4. Go to APIs & Services > Credentials, find your client, and click the download icon to get the JSON
5. Save the file as ~/.mailbox-mcp/oauth-keys.json

4. Authenticate

In Claude Code, run: authenticate alias="personal" provider="gmail" email="you@gmail.com"

This opens a browser window to complete the OAuth flow. Your tokens are stored locally in ~/.mailbox-mcp/accounts/.

Add an IMAP Account

In Claude Code, run:

authenticate alias="work" provider="imap" email="you@company.com" host="imap.company.com" smtpHost="smtp.company.com" username="you@company.com" password="your-app-password"

Credentials are encrypted at rest using AES-256-GCM.

Add a JMAP Account

In Claude Code, run:

authenticate alias="fastmail" provider="jmap" email="you@fastmail.com" host="fastmail.com" username="you@fastmail.com" password="y

... [View full README on GitHub](https://github.com/jgalea/mailbox-mcp#readme)