What is Maddy used for?

Maddy is a composable all-in-one mail server written in Go that handles SMTP, IMAP and email authentication in a single daemon. It is a good fit for self-hosting email for a small domain and replacing a multi-daemon mail stack.

Is Maddy open source?

Yes. Maddy is open source under the GPL-3.0 licence. Its source code is on GitHub at foxcpp/maddy and is written mainly in Go.

Yes. Maddy is open source, so the software itself is free to use.

Can I self-host Maddy?

Yes. Maddy can be self-hosted on your own server or infrastructure; there is no official hosted version.

What is Maddy an alternative to?

Maddy is an open-source alternative to Gmail, Fastmail and Zoho Mail. Other open-source alternatives to Gmail include Mailu, Mox and docker-mailserver.

Is Maddy actively maintained?

Yes. The most recent commit to Maddy was on 16 September 2026, and the latest release is v0.9.5, published on 23 May 2026. The project has 6.1k stars on GitHub.

Maddy: open-source alternative to Gmail, Fastmail, Zoho Mail

About Maddy

Maddy Mail Server is a composable all-in-one mail server written in Go. It implements the functions needed to run an email server: it sends messages over SMTP as an MTA, accepts messages over SMTP as an MX and stores messages while providing access to them over IMAP.

It also implements the auxiliary protocols needed to keep email reasonably secure, including DKIM, SPF, DMARC, DANE and MTA-STS. The project positions itself as a replacement for a stack made of Postfix, Dovecot, OpenDKIM, OpenSPF, OpenDMARC and similar tools, using one daemon with a uniform configuration and low maintenance cost.

The README is candid that IMAP storage is still in beta. For a stable and feature-rich implementation of that part, the maintainers suggest using Dovecot instead, and Maddy can still handle message delivery. Maddy is licensed under GPL-3.0, and a setup tutorial, documentation, an IRC channel and a mailing list are available.

Key features

SMTP sending and receiving
IMAP message storage (beta)
DKIM, SPF and DMARC support
DANE and MTA-STS support
Single daemon with uniform configuration

Good fit for

→Self-hosting email for a small domain
→Replacing a multi-daemon mail stack

Built with: Go
Tags: mail-server; smtp; imap; email; dkim; dmarc; go; self-hosted

Maddy: questions and answers

What is Maddy used for?: Maddy is a composable all-in-one mail server written in Go that handles SMTP, IMAP and email authentication in a single daemon. It is a good fit for self-hosting email for a small domain and replacing a multi-daemon mail stack.
Is Maddy open source?: Yes. Maddy is open source under the GPL-3.0 licence. Its source code is on GitHub at foxcpp/maddy and is written mainly in Go.
Is Maddy free?: Yes. Maddy is open source, so the software itself is free to use.
Can I self-host Maddy?: Yes. Maddy can be self-hosted on your own server or infrastructure; there is no official hosted version.
What is Maddy an alternative to?: Maddy is an open-source alternative to Gmail, Fastmail and Zoho Mail. Other open-source alternatives to Gmail include Mailu, Mox and docker-mailserver.
Is Maddy actively maintained?: Yes. The most recent commit to Maddy was on 16 September 2026, and the latest release is v0.9.5, published on 23 May 2026. The project has 6.1k stars on GitHub.