karti-ai
9812e25973
Design of record for OpenMail — one Go binary (smtpd/core/sender/mcp) + Postgres + object storage on a VPS. Covers inbound SMTP/MIME/threading, outbound deliverability (relay-default, self-host opt-in), data model, AgentMail-shaped v0 API + MCP server, and an MVP milestone path. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
OpenMail
A self-hosted, AI-native mailbox for agents — open-source infrastructure that gives an AI agent its own real email inbox (receive, parse, thread, search, send) on a box you control.
Think "Gmail for agents, self-hosted." A single Go service + Postgres + object storage you run on a VPS, exposing a clean REST API (and an MCP server) so any agent can own an address, read its mail as structured threads, and reply.
Status: private WIP. This is a personal learning project and a self-hosting alternative in a space that hosted products (e.g. AgentMail) serve well. Keep it private. Don't reference it in any job application, PR, or interview, and shelve it if it would ever conflict with an employer. It was designed only from public API surfaces and public RFCs — nothing proprietary.
See ARCHITECTURE.md for the design.
Why
The hard, valuable part of an agent-mailbox product is not the API — it's the mail plumbing: receiving over SMTP/MX, sending with real deliverability (SPF/DKIM/DMARC, IP reputation), parsing MIME, threading, and storage at scale. OpenMail is an exercise in building that plumbing properly, self-hostable, with an agent-first API on top.
Goals
- Self-hostable in one
docker compose upon a single VPS, scaling to a small fleet later. - Agent-first API — persistent inboxes, structured threads,
extracted_text(quoted-history stripped), labels, search, drafts, webhooks/WebSocket events. - AgentMail-API-shaped where reasonable, so existing agent tooling/MCP can point at a self-hosted endpoint with minimal change. (Compatibility is a non-goal where it conflicts with a cleaner design.)
- Deliverability taken seriously — DKIM signing, SPF/DMARC guidance, and a pluggable send path (self-host SMTP or relay through SES/Postmark) because reputation is the real moat.
Non-goals (for v1)
- A hosted multi-tenant SaaS. OpenMail is self-host-first.
- Beating a mature provider on deliverability out of the box — that takes IP warmup and time.
- A webmail UI. The product is the API + MCP; humans use their own client or the CLI.