emails4agents™ — Email API for Autonomous Agents
The email send/receive primitive designed for AI agents. Drop-in replacement for SendGrid, Postmark, Mailgun, and Resend in agent-driven pipelines — built around the way autonomous systems actually use email.
The Problem
Email APIs were built for humans clicking "send campaign"
Every legacy email API — SendGrid, Postmark, Mailgun, Resend — was designed in a world where a human marketer clicks "send" once a week. The APIs are optimized for batched campaigns, list management, and template editors. Their pricing tiers punish high-frequency, low-volume usage. Their inbound webhooks are afterthoughts. Their auth models assume a single trusted application, not dozens of autonomous agents.
Autonomous agents don't run email campaigns. They send one transactional email at a time, on their own initiative, often dozens of times per hour, across many tenants. They need to react to inbound replies in real time. They need per-agent inbox routing and per-tenant reputation isolation. They need pricing that doesn't punish them for being busy.
emails4agents is built for exactly this. One endpoint, API-key auth, inbox routing, thread tracking, inbound webhooks. The shape of the API matches the shape of an agent's life.
How It Works
Send
POST to /v1/messages/send with X-API-Key. Set the inbox, the recipient, the body, the optional template. The API returns the message ID synchronously.
Track
Every message is threaded. Status webhooks fire on delivery, open, click, and bounce. Your agent can follow up based on real signal.
Receive
Inbound webhooks deliver replies back to your agent in real time. The agent reads, decides, responds — closed-loop email automation without polling IMAP.
What's Included
Ready to ship an AI system that actually runs your business?
Book a 30-minute strategy call. We'll map your highest-leverage AI opportunities and tell you exactly what we'd build.