MepMail

MepMail is an open-source email platform that combines a transactional email API and SMTP relay (Send) with business mailboxes on your own domain (Mail, also called Correio). It is built for products, teams and AI agents, and the code is published under AGPL-3.0 with a hosted cloud option and a self-hosted option. Delivery runs on Amazon SES.

What It Is

MepMail puts two kinds of email in one account on the same verified domain. Send covers application email such as sign-ups, password resets, receipts, notifications and marketing broadcasts, through an API, SMTP or MCP. Mail provides real mailboxes for people and AI agents, with a webmail and desktop apps for Windows and Linux.

The repository positions it as an open-source alternative to Resend, SendGrid, Mailgun and Postmark for sending, and to a Google Workspace or Microsoft 365 inbox for your domain.

How Send works

The API follows Resend's request and response shapes, so the Resend SDK can be pointed at MepMail by changing the base URL and key. Send supports batch sends, idempotency keys, an SMTP relay, guided domain DNS verification (including bring-your-own DKIM), signed webhooks, contacts and segments, templates, broadcasts, one-click unsubscribe headers and an automatic suppression list. A CLI command, npx @mepmail/cli migrate --from resend, copies contacts, templates, webhooks, domains and suppressions from a Resend account. The site says each email is run through 21 deliverability checks, and that sending slows or pauses when bounce or complaint rates climb.

Mailboxes for people and agents

Mail offers mailboxes on your domain with aliases, a smart inbox (People, Notifications, Newsletters), snooze, scheduled send, undo send, folders and rules. You can import existing mail over IMAP, or connect Gmail, iCloud, Yahoo, Zoho or IMAP accounts. Agents get their own mailbox, read and draft replies, and you choose whether they send directly or wait for approval of each reply.

Agent and MCP integration

An official MCP server is available hosted with OAuth or locally via npx -y @mepmail/mcp, for clients such as Claude, Cursor and Codex. An n8n community node adds a new-mail trigger and mailbox operations. The web app also serves agent-discovery files like llms.txt.

Self-hosting

Self-hosting uses Docker Compose and requires an AWS account with SES access. The README notes that the self-hosting guide does not yet cover the business mailboxes. The latest listed release is desktop-v1.0.3, a Linux desktop build published 2026-10-14.