Building a Programmable Temporary Email Infrastructure from Scratch

Temporary email services have existed since the early 2000s. Most of them are browser toys — you visit a page, get an address, maybe wait a few minutes, refresh, and copy a confirmation code. They work for human interaction. They fail completely for automation. If you have ever tried to drive one of these services programmatically — from a test suite, a browser automation script, or an AI agent — you know the problems: no API, unreliable polling, addresses you can't control, expiration logic that races with your script, and no way to authenticate access. They are single-user, interactive services dressed up as infrastructure. This article describes how we built a different thing: a programmable temporary email infrastructure with a real API, a real SMTP ingestion layer, deterministic expiration, WebSocket-based event propagation, and first-class support for AI agents via an MCP server. Everything is async, everything is observable, and the production environment is defined entirely in