Mailu is a Docker-based self-hosted mail server, positioned as an alternative to hosted email services or a self-built Postfix/Dovecot setup. It provides common mail capabilities such as SMTP/IMAP, webmail, an administration interface, anti-spam, and antivirus.

Deployment requires familiarity with Docker, DNS, TLS, and MX/SPF/DKIM/DMARC configuration. The available materials do not specify fixed resource requirements, so capacity should be planned according to the number of users. Users in China should confirm whether their cloud provider supports port 25, reverse DNS, and mail reputation requirements; it should not be considered equivalent to WeChat ecosystem integration.