email59

Send transactional email from AI agents: sign up by email code, no domain or DNS setup. Free address and list checks need no key.

GitHub

Hosted MCP Server

npx add-mcp 'https://email59.com/v1/mcp'

Installs into Claude Code, Codex, Cursor and more

Documentation

email59 MCP server

Send transactional email from AI agents: sign up by email code, no domain or DNS setup.

email59's MCP server lets an agent send email on its own. It signs up by asking for a 6-digit code at an address it can read, then uses the session key for everything else. Mail goes out from a name you choose at email59.com, so there's no domain to verify before the first send. The free checks (check_email, check_list) need no sign-in.

This is a hosted remote server (Streamable HTTP). There is nothing to install or run: point your MCP client at the URL below. This repository holds the docs, the logo and the registry entry; the server itself runs at email59.com.

Endpoint: https://email59.com/v1/mcp
Docs: https://email59.com/docs.html#mcp
Website: https://email59.com

Connect

Claude Code:

claude mcp add --transport http email59 https://email59.com/v1/mcp

Gemini CLI (this repo is a Gemini CLI extension):

gemini extensions install https://github.com/icedsg/email59-mcp

Claude Desktop, Cursor, Cline, VS Code and other clients that read an mcpServers block:

{
  "mcpServers": {
    "email59": {
      "type": "http",
      "url": "https://email59.com/v1/mcp",
      "headers": { "Authorization": "Bearer ${EMAIL59_KEY}" }
    }
  }
}

No key yet? Leave the header out, call the auth tool with your email, then call it again with the code to get one.

Tools

Tool	What it does
`auth`	Sign up or sign in by a 6-digit email code; returns a session key.
`send_email`	One email to one recipient: codes, receipts, alerts.
`send_campaign`	A marketing email to a list; the unsubscribe link is added for you.
`check_email`	Free deep check of an address: format, MX, SPF, DMARC, DKIM, MTA-STS, BIMI, disposable and role addresses. No key needed.
`check_list`	The same check for a whole mailing list (emails or CSV text).
`validate_email`	Quick verdict before sending: ok, invalid, no_mx, disposable, role.
`verify_start` / `verify_check`	Send a one-time code to an address and check it (sign-up, sign-in, confirming an email).
`block` / `unblock` / `list_blocklist`	Addresses and domains this account never sends to.
`add_unsubscribe`	Record an opt-out so campaigns skip that address.
`get_account` / `update_account`	Today's allowance and usage; the name, company and brand your email goes out under.
`create_api_key` / `list_api_keys`	Long-lived keys, including test keys whose email is stored instead of delivered.
`list_test_messages`	Read what was sent with a test key.
`get_pricing` / `buy_pack` / `order_status`	What's on offer, and a checkout link for a person to pay. The agent never pays.

Every tool carries a title and readOnlyHint / destructiveHint / openWorldHint annotations.

Worth knowing: email is sent from @email59.com. Every email carries an unsubscribe link and a "system generated" line, and accounts that send unsolicited mail are closed.

Check it from a terminal

curl -s https://email59.com/v1/mcp -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}'