Fastmail
Enables AI assistants to interact with Fastmail services, providing tools for comprehensive email management, contact searching, and calendar event coordination via the JMAP API. It supports advanced features like threaded conversations, attachment h
What is Fastmail?
Fastmail is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to enables ai assistants to interact with fastmail services, providing tools for comprehensive email management, contact searching, and calendar event coordination via the jmap api. it supports advanced ...
Enables AI assistants to interact with Fastmail services, providing tools for comprehensive email management, contact searching, and calendar event coordination via the JMAP API. It supports advanced features like threaded conversations, attachment h
This server falls under the Communication category on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- Enables AI assistants to interact with Fastmail services, pr
Use Cases
Maintainer
Works with
Installation
Manual Installation
npx fastmail-mcp-serverConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use Fastmail
Fastmail MCP Server is a TypeScript MCP server that connects AI assistants to Fastmail's JMAP API, exposing 38 tools for complete email management (list, search, send, reply, draft, move, delete, bulk operations), contact lookup, calendar event management, and account statistics. It supports threaded conversations with proper In-Reply-To and References headers, attachment listing and downloading, advanced multi-criteria search, and label vs folder operations. It is the go-to integration for Fastmail users who want to manage their inbox, contacts, and calendar through natural language in Claude Desktop or any MCP client.
Prerequisites
- Node.js 20 or later installed
- A Fastmail account with API access enabled
- A Fastmail API token (generated from Settings > Privacy & Security > Connected apps & API tokens)
- An MCP-compatible client (Claude Desktop, Cursor, etc.)
Get your Fastmail API token
Log in to Fastmail web, go to Settings > Privacy & Security > Connected apps & API tokens, click 'Manage API tokens', then 'New API token', and copy the generated token.
Clone the repository and install dependencies
Clone the Fastmail MCP server repository and install its npm dependencies.
git clone https://github.com/MadLlama25/fastmail-mcp.git
cd fastmail-mcp
npm install
npm run buildConfigure environment variables
Set the required FASTMAIL_API_TOKEN environment variable. Optionally configure FASTMAIL_BASE_URL (defaults to https://api.fastmail.com) and FASTMAIL_DOWNLOAD_DIR for attachment downloads.
export FASTMAIL_API_TOKEN="your_api_token_here"
export FASTMAIL_BASE_URL="https://api.fastmail.com"
# Optional: custom attachment download directory
export FASTMAIL_DOWNLOAD_DIR="/path/to/downloads"Add to your MCP client configuration
Configure your MCP client to run the server via npx from the GitHub source, passing the API token as an environment variable.
{
"mcpServers": {
"fastmail": {
"command": "npx",
"args": ["--yes", "github:MadLlama25/fastmail-mcp", "fastmail-mcp"],
"env": {
"FASTMAIL_API_TOKEN": "your_api_token_here",
"FASTMAIL_BASE_URL": "https://api.fastmail.com"
}
}
}
}Alternatively install as a Claude Desktop Extension (DXT)
Build and pack a .dxt file, then drag it into Claude Desktop. Claude stores the API token encrypted and prompts you for it on install.
npm run build
npx @anthropic-ai/dxt pack
# Then drag fastmail-mcp.dxt into Claude DesktopFastmail Examples
Client configuration
Claude Desktop configuration using npx to run the server directly from GitHub with the API token injected via env.
{
"mcpServers": {
"fastmail": {
"command": "npx",
"args": ["--yes", "github:MadLlama25/fastmail-mcp", "fastmail-mcp"],
"env": {
"FASTMAIL_API_TOKEN": "your_api_token_here",
"FASTMAIL_BASE_URL": "https://api.fastmail.com",
"FASTMAIL_DOWNLOAD_DIR": "/Users/yourname/Downloads/fastmail-mcp"
}
}
}
}Prompts to try
Example prompts that use Fastmail's 38 tools across email, contacts, calendar, and bulk operations.
- "Show me the 10 most recent unread emails in my inbox and summarize each one"
- "Search for emails from [email protected] with attachments in the last 30 days and download the attachments"
- "Reply to the email with subject 'Project update' thanking them and asking for the next meeting time"
- "Find the contact named Jane Doe and show me her email address"
- "List my calendar events for the next 7 days and tell me if I have any conflicts"
- "Move all emails from [email protected] to the Newsletters folder"Troubleshooting Fastmail
Authentication fails with 'Unauthorized' error
Verify that FASTMAIL_API_TOKEN is set correctly and matches an active token in Fastmail > Settings > Connected apps & API tokens. Tokens must have the mail scope enabled. Generate a new token if the existing one has been revoked.
Attachment downloads fail or save to unexpected location
Set FASTMAIL_DOWNLOAD_DIR to a fully qualified path you have write access to. The default is ~/Downloads/fastmail-mcp/. If savePath is omitted from download_attachment, the tool returns a download URL instead of writing to disk.
Replies do not appear threaded in Fastmail
Use the reply_email tool rather than send_email for replies — it automatically fetches the original email's Message-ID and builds proper In-Reply-To and References headers. Using send_email without these headers creates a new unthreaded conversation.
Frequently Asked Questions about Fastmail
What is Fastmail?
Fastmail is a Model Context Protocol (MCP) server that enables ai assistants to interact with fastmail services, providing tools for comprehensive email management, contact searching, and calendar event coordination via the jmap api. it supports advanced features like threaded conversations, attachment h It connects AI assistants to external tools and data sources through a standardized interface.
How do I install Fastmail?
Follow the installation instructions on the Fastmail GitHub repository. Clone the repo, install dependencies, and add the server config to your AI client.
Which AI clients work with Fastmail?
Fastmail works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is Fastmail free to use?
Yes, Fastmail is open source and available under the MIT License license. You can use it freely in both personal and commercial projects.
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