■ Lob
Direct mail API — agents can programmatically send physical letters, postcards, and checks to any address.
Lob is a developer-first API for sending physical mail: letters, postcards, and checks. An agent can trigger a physical mailing with a single API call — Lob handles printing, addressing, and USPS delivery. Fully automated, no human steps. The canonical infrastructure for agents that need to create a physical paper trail or send physical correspondence.
website: https://www.lob.com
docs: https://docs.lob.com
categories: Virtual Mailbox
tags: direct mail, physical mail, letter, postcard, print, USPS, check
endpoint: https://api.lob.com/v1/
protocols: REST
auth: api-key
pricing: per-call
payment: USD
agent-native: no
human needed: no (fully autonomous)
scope: north-america
status: approved
registered: 2026-03-10
verified: 2026-03-10