Paid services on Base matching “usps”

Check the status and tracking of a physical letter previously sent via POST /api/letters. Returns render status, expected delivery date, and (for certified mail) the USPS tracking number.

Print and mail physical US letters (PDF, HTML, Markdown, DOCX, or image) and postcards via USPS, paid in USDC — with certified/registered proof options and standalone address verification at POST /v1/verify. Integration flow: POST /v1/documents to upload, POST /v1/quotes to lock a fixed USDC price for a recipient, then pay the returned per-quote x402 URL to create and mail the piece. Price is fixe

Multi-carrier package tracking. Live: FedEx, USPS, DHL. In rollout: UPS. Roadmap (returns 'coming soon' to log demand): Canada Post, La Poste, Royal Mail, Australia Post, Evri, Deutsche Post, PostNL, China Post, Japan Post, India Post, Correos, Poste Italiane, Aramex, Yodel, Swiss Post, Correios BR, EMS, OnTrac, Amazon Shipping. Pass tracking_number (and optional carrier='royal_mail' style slug).