Mailu is a mail server distributed as a set of Docker images, intended for anyone who wants to host their own email. The package covers the IMAP, SMTP and Submission protocols, webmail and an administration interface, managesieve, an antivirus scanner and anti-spam measures such as greylisting, SPF and DMARC checks and outgoing DKIM signing. Administrators can set up aliases, domain aliases, quotas and per-domain delegation. Users can enable auto-reply and forwarding. Mailu runs with Docker Compose or on Kubernetes and supports MySQL/MariaDB and PostgreSQL, among others, as its database.
Mailu is free software: its own configuration files, Dockerfiles and code are placed under the MIT licence, and the project ships no proprietary software. Copyright is held by the "Mailu authors"; the project is developed on GitHub and accepts outside contributions. No vendor hosts the data: you run Mailu yourself, so mail and accounts sit on infrastructure of your choice, for example in an EU data centre. Operations, updates and security of the server remain your own responsibility.