# OpenMail

**An agent-native, self-hosted mail server.** One Go binary that gives an AI agent its own real
email address — receive, parse, thread, search, and send actual SMTP mail on a box you control —
behind a clean REST API and an MCP server.

Think "AgentMail, but self-hosted and MIT-licensed." OpenMail embeds the battle-tested mail
internals of [Mox](https://github.com/mjl-/mox) (also MIT) for the hard, correctness-critical
plumbing — DKIM, SPF/DMARC, DANE + MTA-STS secure delivery, real-world MIME parsing, spam
filtering — and layers a native, agent-shaped data model (Postgres + object storage) and API on top.

> **Status: early WIP, private during initial build.** Will be released MIT-licensed and public.
> Designed only from public RFCs and public API surfaces — nothing proprietary.

License: **MIT** — see [LICENSE](./LICENSE). Builds on Mox (MIT) and the `emersion/go-*` mail
libraries. See **[ARCHITECTURE.md](./ARCHITECTURE.md)** for the design of record.

## Why

The valuable, hard 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, DANE/MTA-STS, IP
reputation), parsing messy MIME, threading, and storage. Hosted products (AgentMail and similar)
solve this well but are closed and run on someone else's infrastructure. OpenMail's bet: you can
**embed** an existing MIT-licensed, production-grade Go mail stack instead of rebuilding it, and
spend your effort on the part nobody has done well — the **agent-native** layer.

## What makes it agent-native

- **Persistent inboxes as first-class API resources**, provisioned in one call.
- **Structured threads**, not raw IMAP — `In-Reply-To`/`References` stitched into conversations.
- **`extracted_text`** — reply content with quoted history stripped, so an agent reads the new part.
- **MCP server** — an agent (Claude Code, etc.) owns and operates its mailbox directly as tools.
- **Webhooks + WebSocket** `message.received` events — agents react to mail in real time.
- **AgentMail-API-shaped** REST where reasonable, so existing tooling points at a self-hosted base URL.

## Goals

- **Self-hostable** in one `docker compose up` on a single VPS; scales to a fleet later.
- **Deliverability taken seriously** — self-host SMTP send with DKIM + DANE + MTA-STS via Mox's
  delivery stack, *or* a relay backend (SES/Postmark/Resend) for inbox placement on day one.
- **Single static Go binary** with subcommands; Postgres + S3-compatible object store as the only deps.
- **Genuinely MIT** — every embedded dependency is MIT/BSD; no GPL/AGPL anywhere in the tree.

## Non-goals (for v1)

- A hosted multi-tenant SaaS. OpenMail is self-host-first (multi-tenant `pods` exist, but you run it).
- A full webmail UI. The product is the API + MCP; humans use their own client.
- Beating a mature provider's deliverability on day one — self-host IP reputation takes warmup + time;
  the relay backend exists for exactly that gap.