MCP Server for Direct Mail

What is this

Mailsnail is an MCP server. It exposes a small, well-typed set of tools for sending physical mail and gets out of the way. Any client that speaks Model Context Protocol — Claude Desktop, Claude Code, Cursor, Codex CLI, the OpenAI Agents SDK, custom hosts — can use it.

Tools

• verify_address: validate and normalize a US address. Free.
• preview_letter: proof PDF + exact price without charging — the recommended first step (managed mode).
• send_letter: compose and mail a physical letter to any US address.
• send_postcard: send a postcard with a custom front image.
• get_letter: check delivery state by ID.
• list_letters: paginate through sent mail (Lob mode only).
• cancel_letter: cancel before production (BYO Click2Mail/Lob).

Full schemas live in /llms-full.txt and /openapi.json.

Connection

Transport: stdio via npx -y mailsnail. Copy-paste config for every major client lives on the setup page.

Pricing

No signup, no subscription — your agent pays per piece via Stripe: $1.50 for a first-class letter, $9.00 for certified, $1.00 for a postcard. If a piece fails to mail, the charge is auto-refunded.

If you're evaluating direct-mail-from-agents and want a real conversation, email hello@mailsnail.dev.

{
  "mcpServers": {
    "mailsnail": {
      "command": "npx",
      "args": [
        "-y",
        "mailsnail"
      ],
      "env": {
        "MAIL_PROVIDER": "managed",
        "MAIL_API_BASE_URL": "https://api.mailsnail.dev"
      }
    }
  }
}