Which Email Clients Work with Claude Desktop and MCP?

Checked November 6, 2026

Three mail products we checked have an MCP server of their own: Postage, a Mac app whose server runs on your machine for any IMAP account; Superhuman Mail, hosted, for Gmail and Outlook on Business and Enterprise plans; and Fastmail, hosted, for Fastmail accounts. Mimestream doesn't list one, and Apple's MCP announcement names Keynote, Pages and Numbers, not Mail.

At a glance

	Postage	Superhuman Mail	Fastmail	Mimestream
MCP server	Built into the Mac app	Superhuman Mail MCP	api.fastmail.com/mcp	Not listed on its site
Where it runs	On your Mac, 127.0.0.1 only	Superhuman's service	Fastmail's service	Not applicable
Accounts	Any IMAP account that signs in with a password or app password	Gmail and Outlook	Fastmail	Google accounts
Can the agent send?	No. You press Send in Postage	Yes. Every send needs your approval by default	Yes, if you grant send access	Not applicable
Attachments over MCP	Text of PDF, text, HTML, CSV, JSON and XML	Not listed	Not supported at this time	Not applicable
Price	$39 once	Business: $33 per member a month billed yearly, $40 billed monthly	Not listed for MCP	$4.99 a month or $49.99 a year

Superhuman facts from superhuman.com/plans and superhuman.com/mail/features/email-mcp. Fastmail facts from fastmail.com/blog/an-mcp-server-for-fastmail and its help article on connecting AI tools. Mimestream facts from mimestream.com. All checked 2026-11-06.

How each one connects to Claude Desktop

Postage: Settings > Agents > Install in Claude Desktop hands Claude Desktop an extension. A custom connector won't work, because Claude reaches those from Anthropic's cloud and Postage's server stays on your Mac.
Superhuman Mail: its MCP page has a Connect to Claude button, and the MCP needs a Business or Enterprise plan.
Fastmail: add the server URL to your AI client and approve one of three access levels on Fastmail's consent screen: read-only, write or send.

Mail apps with no MCP server listed

Mimestream is a native Gmail app whose site doesn't list an MCP server. Apple Mail doesn't appear in Apple's October 2026 announcement of MCP support, which covers Keynote, Pages and Numbers. Scripts from other developers can drive a mail app through automation, and you manage their install, updates and macOS permissions yourself. See what to check before you connect one.

If your mail is on Outlook

Postage can't add Outlook.com, Hotmail or Microsoft 365 accounts yet. Microsoft turned off password sign-in for mail apps, and Postage doesn't support Microsoft's own sign-in. Of the products above, Superhuman names Outlook.

Which to choose

Several providers, or iCloud, Yahoo or your own domain: Postage, $39 once, with every account in one app.
A team on Gmail or Outlook already using Superhuman: its Mail MCP.
All your mail on Fastmail, and you're happy with a hosted server: Fastmail's own. Postage also works with Fastmail if you want the server on your Mac and a mail app showing what the agent did.

Questions

Does Apple Mail work with Claude?

Apple's announcement of MCP support names Keynote, Pages and Numbers, not Mail. Postage works with the same iCloud and IMAP accounts you may have in Apple Mail, and both apps can run side by side.

Does Mimestream work with Claude?

Mimestream's site doesn't list an MCP server or AI features. Postage connects to Gmail accounts too and has a server built in.

Which email client works with Claude Code?

Postage has a one-line setup for Claude Code, copied from Settings > Agents. Claude Code also accepts remote MCP servers, so you can add a hosted one by its URL.

Get Postage

A fast, native Mac email client with the MCP server built in. $39 once, no subscription.

One-time purchase, no subscription. Notarized by Apple. macOS 14 Sonoma or later.