Mailsink

Model Context Protocol server for MailSink — programmatic temporary email inboxes for AI agents and test automation.

Gives your agent eight typed tools for provisioning disposable addresses, waiting on signup emails, extracting OTP codes and magic links, and cleaning up after itself. Works in Claude Code, Claude Desktop, Cursor, Windsurf, and any other MCP-aware client.

Install

npm install -g @mailsink/mcp

Or run via npx without installing:

npx @mailsink/mcp

Get an API key

1. Sign in at https://mailsink.dev/app with GitHub.

2. Copy the key from the one-time reveal. Store it in your password manager or .env.

3. Export it so the MCP server can read it:

   export MAILSINK_API_KEY="msk_..."
   

Free tier is 50 inboxes/month and includes MCP. Pro ($15/mo) and Team ($49/mo) lift the inbox cap, raise email size limits, extend TTL, and bump request rates. See pricing.

Configure your client

Claude Code

claude mcp add mailsink -- npx -y @mailsink/mcp

Claude Desktop / Cursor / Windsurf

Add to the mcpServers section of the client's config file:

{
  "mcpServers": {
    "mailsink": {
      "command": "npx",
      "args": ["-y", "@mailsink/mcp"],
      "env": {
        "MAILSINK_API_KEY": "msk_..."
      }
    }
  }
}

Restart the client. You should see the mailsink server listed with its eight tools.

Tools

Tool	Purpose
create_inbox	Provision a throwaway address. Returns email, id, expires_at.
list_inboxes	List active inboxes on the account.
wait_for_email	Block up to timeout seconds (max 120) for any email to arrive.
get_verification_code	Extract the most recent OTP from the inbox (polls until found or timeout).
get_verification_link	Extract the most recent magic link.
list_messages	Summaries of all messages in an inbox.
get_message	Full content of a specific message by ID.
delete_inbox	Burn an inbox immediately.

Example agent flow

> Sign me up for Figma, capture the verification code, confirm, and
> tell me the plan once you're in.

[agent invokes]
  create_inbox()                                → [email protected]
  [agent fills the Figma signup form with that address]
  wait_for_email(inbox_id)                      → blocks 30s…
                                                → returns email + OTP
  [agent types the OTP into the Figma form]
  delete_inbox(inbox_id)                        → cleanup

No webhook plumbing. No IMAP credentials. No parsing MIME.

Environment variables

• MAILSINK_API_KEY (required) — your account's API key.
• MAILSINK_API_URL (optional, default https://api.mailsink.dev) — override for self-hosted or dev API.

Source

https://github.com/heocoi/mailsink/tree/main/mcp

License

MIT — see LICENSE.