Connect checkmails to your AI

Verify email deliverability from Claude, Cursor, or any MCP client. checkmails exposes a remote MCP (Model Context Protocol) server. Connect in one of two ways: sign in from your browser (no key to paste) or use an API key.

Server URL

Option 1 — Sign in (recommended, no key to paste)

Your MCP client opens a browser window; you sign in to checkmails and approve — done. Nothing to copy. Works with any client that supports OAuth (Claude, Cursor, …).

Claude Code

claude mcp add --transport http checkmails https://checkmails.eu/api/mcp

Cursor / Claude Desktop / generic — add this entry; the client prompts you to sign in on first use:

{
  "mcpServers": {
    "checkmails": {
      "type": "http",
      "url": "https://checkmails.eu/api/mcp"
    }
  }
}

Option 2 — API key (headless, CI, servers)

For automated or server-side use without a browser, authenticate with an API key (paid plan) — get yours at /app, then replace chk_your_key below.

Claude Code

claude mcp add --transport http checkmails https://checkmails.eu/api/mcp --header "Authorization: Bearer chk_your_key"

Cursor / Claude Desktop / generic

{
  "mcpServers": {
    "checkmails": {
      "type": "http",
      "url": "https://checkmails.eu/api/mcp",
      "headers": { "Authorization": "Bearer chk_your_key" }
    }
  }
}

Tools

The server speaks JSON-RPC 2.0 (protocol revision 2025-06-18) and exposes three tools:

• verify_email(email) — verify a single address by SMTP (RCPT TO) without sending any message. Costs 1 credit. Returns a verdict (valid / invalid / indeterminate), a risk score (0–100) and diagnostic flags.
• verify_bulk(emails[], consent?) — verify a batch of up to 1000 addresses asynchronously. Returns a job_id. Costs 1 credit per address with a definitive verdict (valid or invalid). Optional consent flag to acknowledge recipient consent.
• get_job(job_id) — get the status and results of a bulk job.

Indeterminate results (catch-all, uncertain iCloud) are never billed.