Self-hostable Go + Postgres email relay that authenticates inbound SPF/DKIM, HMAC-signs delivery headers, and adds a human-in-the-loop approval gate for outbound agent mail.
Key Takeaways
Inbound SMTP is SPF/DKIM verified; every delivery gets HMAC-SHA256-signed X-E2A-Auth-* headers with a 5-minute replay window.
Two delivery modes: webhook POST for cloud agents (requires public URL) and WebSocket fan-out for local agents with no public URL needed.
HITL gate holds outbound messages at HTTP 202; reviewers approve via dashboard, magic-link email, or CLI before SMTP dispatch.
Python and TypeScript SDKs gate field access behind signature verification by default, raising UnverifiedEmailError on unsigned payloads.
CLI supports OpenAI Responses API forwarding: e2a listen --forward can auto-reply using a local model endpoint.
