What is Mail-in-a-Box used for?

Mail-in-a-Box turns a fresh Ubuntu server into a complete self-hosted mail server with webmail, DNS, spam filtering and automatic TLS. It is a good fit for self-hosting personal or family email and small organizations running their own mail.

Is Mail-in-a-Box open source?

Yes. Mail-in-a-Box is open source under the CC0-1.0 licence. Its source code is on GitHub at mail-in-a-box/mailinabox and is written mainly in Python.

Is Mail-in-a-Box free?

Yes. Mail-in-a-Box is open source, so the software itself is free to use.

Can I self-host Mail-in-a-Box?

Yes. Mail-in-a-Box can be self-hosted on your own server or infrastructure; there is no official hosted version.

What is Mail-in-a-Box an alternative to?

Mail-in-a-Box is an open-source alternative to Gmail, Google Workspace, Fastmail and Proton Mail. Other open-source alternatives to Gmail include Stalwart, Mailcow and Mailu.

Is Mail-in-a-Box actively maintained?

Yes. The most recent commit to Mail-in-a-Box was on 26 September 2026, and the latest release is v77, published on 26 September 2026. The project has 15k stars on GitHub.

Mail-in-a-Box: open-source alternative to Gmail

About Mail-in-a-Box

Mail-in-a-Box helps individuals take back control of their email by providing a one-click, easy-to-deploy mail server in a box. It turns a fresh Ubuntu 22.04 LTS 64-bit machine into a working mail server by installing and configuring the required components. There are no user-configurable setup options, so it is designed to just work.

The installed components include Postfix for SMTP, Dovecot for IMAP, Nextcloud for CardDAV and CalDAV, z-push for Exchange ActiveSync, and Roundcube webmail. It adds spam filtering with SpamAssassin and greylisting with Postgrey, DNS with SPF, DKIM, DMARC, DNSSEC, DANE TLSA, MTA-STS and SSHFP records set automatically, and TLS certificates from Let's Encrypt. Backups use duplicity, with ufw, fail2ban and munin for protection and monitoring.

Project goals include making a good mail server easy to deploy, promoting decentralization and privacy, and keeping configuration automated, auditable and idempotent. It deliberately does not aim to be customizable by power users. Mail-in-a-Box is written in Python, released into the public domain under CC0-1.0, and has a Code of Conduct for contributors.

Key features

One-click mail server on Ubuntu 22.04
Postfix SMTP and Dovecot IMAP
Roundcube webmail and Nextcloud contacts
Automatic SPF, DKIM, DMARC and DNSSEC setup
Let's Encrypt TLS certificate provisioning
Backups, fail2ban and health monitoring

Good fit for

→Self-hosting personal or family email
→Small organizations running their own mail

Built with: Python
Tags: mail-server; email; smtp; imap; self-hosted; webmail; dns; ubuntu

Mail-in-a-Box: questions and answers

What is Mail-in-a-Box used for?: Mail-in-a-Box turns a fresh Ubuntu server into a complete self-hosted mail server with webmail, DNS, spam filtering and automatic TLS. It is a good fit for self-hosting personal or family email and small organizations running their own mail.
Is Mail-in-a-Box open source?: Yes. Mail-in-a-Box is open source under the CC0-1.0 licence. Its source code is on GitHub at mail-in-a-box/mailinabox and is written mainly in Python.
Is Mail-in-a-Box free?: Yes. Mail-in-a-Box is open source, so the software itself is free to use.
Can I self-host Mail-in-a-Box?: Yes. Mail-in-a-Box can be self-hosted on your own server or infrastructure; there is no official hosted version.
What is Mail-in-a-Box an alternative to?: Mail-in-a-Box is an open-source alternative to Gmail, Google Workspace, Fastmail and Proton Mail. Other open-source alternatives to Gmail include Stalwart, Mailcow and Mailu.
Is Mail-in-a-Box actively maintained?: Yes. The most recent commit to Mail-in-a-Box was on 26 September 2026, and the latest release is v77, published on 26 September 2026. The project has 15k stars on GitHub.