Fastmail MCP Server

A Model Context Protocol (MCP) server for Fastmail. Enables any MCP-compatible AI assistant to read, search, send, and manage emails, calendars, and contacts in a Fastmail account via the JMAP protocol.

- Node.js 18 or later
- A Fastmail account (Standard or Professional plan)
- A Fastmail API token with JMAP access
- Log in toFastmail
- Go toSettings → Privacy & Security → Manage API tokens
- ClickNew API token
- Grant access toMail,Calendars, andContacts(read and write)
- Copy the generated token

npm install @jordonh19/fastmail-mcp-server

{ "mcpServers": { "fastmail": { "command": "npx", "args": ["@jordonh19/fastmail-mcp-server"], "env": { "FASTMAIL_API_TOKEN": "your-api-token-here" } } } }

export FASTMAIL_API_TOKEN="your-api-token-here" claude mcp add fastmail -- npx @jordonh19/fastmail-mcp-server

Add to your Cursor MCP configuration (.cursor/mcp.json):

{ "mcpServers": { "fastmail": { "command": "npx", "args": ["@jordonh19/fastmail-mcp-server"], "env": { "FASTMAIL_API_TOKEN": "your-api-token-here" } } } }

Add to your Windsurf MCP configuration (~/.codeium/windsurf/mcp_config.json):

{ "mcpServers": { "fastmail": { "command": "npx", "args": ["@jordonh19/fastmail-mcp-server"], "env": { "FASTMAIL_API_TOKEN": "your-api-token-here" } } } }

Add to your VS Code MCP configuration (.vscode/mcp.json):

{ "servers": { "fastmail": { "command": "npx", "args": ["@jordonh19/fastmail-mcp-server"], "env": { "FASTMAIL_API_TOKEN": "your-api-token-here" } } } }

For any MCP-compatible client, run the server with theFASTMAIL_API_TOKENenvironment variable set:

FASTMAIL_API_TOKEN="your-api-token-here" npx @jordonh19/fastmail-mcp-server

The server communicates over stdio by default, following the standard MCP transport protocol. To run over HTTP instead, use the--transportflag:

FASTMAIL_API_TOKEN="your-api-token-here" npx @jordonh19/fastmail-mcp-server --transport http --port 3000

- list_mailboxes: List all mailboxes or folders with roles and email counts.
- create_mailbox: Create a new mailbox or folder.
- rename_mailbox: Rename an existing mailbox or folder.
- delete_mailbox: Delete a mailbox or folder, optionally with force delete.

- list_calendars: List all calendars with names, colors, and visibility.
- get_calendar_events: Search or list calendar events by date range, calendar, or title.
- get_calendar_event: Get full details of a specific calendar event.
- create_calendar_event: Create a new calendar event with location, participants, and alerts.
- update_calendar_event: Update an existing calendar event.
- delete_calendar_event: Delete a calendar event.

- list_address_books: List all address books or contact groups.
- search_contacts: Search contacts by name, email, or other criteria.
- get_contact: Get full details of a specific contact.
- create_contact: Create a new contact with email, phone, organization, and more.
- update_contact: Update an existing contact's information.
- delete_contact: Delete a contact.

- get_identities: List available sender identities.

- check_function_availability: Check which Fastmail feature groups and MCP client capabilities are available, with setup guidance for missing access.

The server supports two transport modes:

Standard input/output transport. Used by most MCP clients (Claude Desktop, Cursor, VS Code, etc.):

FASTMAIL_API_TOKEN="your-token" npx @jordonh19/fastmail-mcp-server

Runs as an HTTP server for remote access or multi-client scenarios:

FASTMAIL_API_TOKEN="your-token" npx @jordonh19/fastmail-mcp-server --transport http --port 3000

The HTTP transport exposes a single/mcpendpoint that supports the MCP Streamable HTTP protocol.

When running in HTTP mode, a built-in web dashboard is available at the server root. It provides:

- Live tool-call log— see every MCP tool invocation in real time via SSE
- Connection tracking— monitor active MCP client connections
- Server uptime— at-a-glance health status

A pre-packaged.dxtextension can be built for one-click installation in Claude Desktop:

This producesfastmail-mcp-server-v<version>.dxtin the project root. Double-click the file (or drag it into Claude Desktop) to install. Claude will prompt for your Fastmail API token on first use.

The server can be configured via environment variables or a JSON config file.

- FASTMAIL_API_TOKEN: Required. Fastmail API token with JMAP access.

Create a.fastmail-mcp.jsonfile in your project root or home directory:

{ "transport": "stdio", "port": 3000 }

The server searches for config files in this order:
- ./.fastmail-mcp.json(current directory)
- ~/.fastmail-mcp.json(home directory)

Environment variables and CLI flags always take precedence over config file values.

SeeCONTRIBUTING.mdfor detailed development guidelines.

git clone https://github.com/Jordonh18/fastmail-mcp-server.git cd fastmail-mcp-server npm install npm run build npm test

FASTMAIL_API_TOKEN="your-token" node dist/index.js

Provides various DingTalk services including contacts, department management, robot messaging, calendar, and tasks.