"National Rail" matching MCP connectors:

Print and mail physical letters and postcards to US postal addresses, plus address verification. Upload PDF/HTML/Markdown/text/DOCX/image documents, get a quote, and pay per call with x402 USDC on Base mainnet or credit card. Supports certified/registered mail with proof of delivery and mail-merge templates.

PhoboMail gives AI agents their own @phobomail.com email address with zero human involvement. Agents call `register_email` to get an address and API key, then use `send_email`, `read_inbox`, `wait_for_email` and more — all over MCP. Ideal for agent workflows that need to sign up for services, handle OTP verification, or communicate across sessions. Hosted on Cloudflare.