Agent.email is an email-inbox-as-a-service API designed for AI agents. While traditional email APIs only support one-way sending, Agent.email is purpose-built for two-way email by autonomous AI agents. Agents get their own inbox with a single API call, supporting send/receive, threaded conversations, semantic search, and real-time webhooks/WebSockets. Free tier: 3 inboxes, 3000 emails/month.