Fastmail MCP Server (Unofficial)

Unofficial Model Context Protocol server for Fastmail integration.

Setup Instructions

1. Get Your Fastmail API Token

1. Log in to Fastmail

2. Go to Settings → Privacy & Security → API tokens

3. Click New API token

4. Give it a name (e.g., "Claude MCP")

5. Select the required scopes: Mail (read/write as needed)

6. Copy the generated token

2. Configure Claude Code

Add the following to your Claude Code MCP settings (~/.claude/claude_desktop_config.json or project .mcp.json):

Security Note: Keep your API token secure. Never commit it to version control. Consider using environment variables or a secrets manager.

Available Tools

mailbox_get

Get mailbox information (folders) - list all mailboxes or get specific ones by ID.

email_query

Query emails with filters and sorting.

• mailboxId (optional): Mailbox ID to search in

• limit (optional, default: 10): Maximum number of emails to return

• from (optional): Filter by sender

• to (optional): Filter by recipient

• subject (optional): Filter by subject text

• hasKeyword (optional): Filter by keyword (e.g., $seen, $flagged)

• notKeyword (optional): Filter by absence of keyword

• before (optional): Filter by date (ISO format)

• after (optional): Filter by date (ISO format)

• sort (optional, default: receivedAt): Sort by property

• ascending (optional, default: false): Sort order

email_get

Get specific emails by their IDs.

• emailIds (required): Array of email IDs to retrieve

• accountId (optional): Account ID (auto-detected if not provided)

• properties (optional): Specific properties to fetch

• fetchTextBodyValues (optional): Fetch text/plain body values

• fetchHTMLBodyValues (optional): Fetch text/html body values

• fetchAllBodyValues (optional): Fetch all text body values

• maxBodyValueBytes (optional): Maximum size in bytes for body values

email_send

Send emails with support for plain text, HTML, or both.

• to (required): Recipient email address

• subject (required): Email subject

• body (required): Plain text body

• htmlBody (optional): HTML body for multipart/alternative emails

• identityId (optional): Identity ID to send from

API Endpoints

• POST /mcp - MCP protocol endpoint

• GET /health - Health check endpoint

Development

This is an unofficial community project and is not affiliated with Fastmail.

Source code and issues: GitHub