Mailu

Mailu is a feature-complete, modular mail server distribution designed for seamless containerized deployment via Docker and Docker Compose. As of 2026, Mailu has solidified its position as the leading open-source alternative to proprietary suites like Microsoft 365 or Google Workspace for organizations demanding total data sovereignty. Its architecture is built on a microservices model, orchestrating industry-standard components including Postfix (MTA), Dovecot (IMAP/POP3), Rspamd (Filtering), and Nginx (Web Frontend). The system is designed to be low-maintenance, providing a web-based administration interface that handles complex configurations such as DKIM signing, DMARC policies, and SSL/TLS certificate management through Let's Encrypt. Technical architects favor Mailu for its small resource footprint and its ability to scale storage independently of the application logic. It supports multiple webmail frontends like Roundcube and SnappyMail, and includes advanced features such as aliasing, domain delegation, and a RESTful API for automated user provisioning. In a landscape increasingly concerned with GDPR compliance and data residency, Mailu provides a robust, audited framework for secure communication without the overhead of legacy mail server management.