Fastmail

You can use the Fastmail MCP Server to give AI assistants secure, read-only access to your Fastmail emails through the JMAP API. It lets you search emails, retrieve full email details, and list mailboxes, while keeping your Fastmail token stored securely and used only for read operations.

How to use

You connect to the server from an MCP client you already use. The server exposes three main actions: search emails by text and mailbox, fetch full email content including attachments, and list all mailboxes with their email counts. Before you start, provide your Fastmail API token in the environment so the server can authenticate with Fastmail.

How to install

Prerequisites include Python 3.12 or newer and a Fastmail account with an API token.

Install the server dependencies and run the local MCP server.

# 1. Clone or download the server project
# (use your preferred method to obtain the code)

# 2. Install Python dependencies
pip install -r requirements.txt

# 3. Create a local environment file and add your token
cp .env.example .env

FASTMAIL_API_TOKEN=your_fastmail_api_token_here

# 4. Run the server locally in stdio mode (default)
python fastmail_mcp.py

# 5. (Optional) Run in HTTP mode on port 8000
python fastmail_mcp.py --http

Configuration and usage notes

Environment variables you will need are provided by you to authenticate with Fastmail. The following variable is required for the MCP server to access your Fastmail data: FASTMAIL_API_TOKEN.

{
  "mcpServers": {
    "fastmail": {
      "command": "python",
      "args": ["/absolute/path/to/fastmail_mcp.py"],
      "env": {
        "FASTMAIL_API_TOKEN": "your_fastmail_api_token_here"
      }
    }
  }
}

Security considerations

The API token grants read access to your Fastmail data. Keep it secure and do not commit it to version control. The MCP server is designed for read-only access to emails and attachments through the JMAP API.

Troubleshooting

If you encounter authentication errors, verify that the token is correct and has the required scopes. If you get no emails in results, broaden your search or confirm the mailbox name is valid using the listed mailboxes.

Testing the MCP server

You can test the MCP server with the MCP Inspector tool to verify that the available endpoints work as expected.

npx @modelcontextprotocol/inspector python fastmail_mcp.py

Available tools

search_emails

Search emails in your Fastmail account by text and mailbox with optional limit and mailbox filter.

get_email

Fetch the full content of a specific email by its email_id from search results.

list_mailboxes

List all mailboxes with their respective email counts.