Apps similar to Poste.io include mailcow: dockerized, which is free and open source. Other options are Foxmail, Mail-in-a-box, Zimbra Collaboration Suite and Mail Server Builder. You can choose from more than 10 Mail Servers like Poste.io for self-hosting, Windows, Linux, the web and Mac.
Mailu is a simple yet full-featured mail server as a set of Docker images. It is free software (both as in free beer and as in free speech), open to suggestions and external contributions.
Turnkey Solutions for the Enterprise Cloud
Installation, Configuration, and Management tools for enterprise email, collaboration, messaging, video conferencing, file sharing, and file transfers.
Fast, safe, heavy mail solution. Web-client access, LAN or WAN self-hosted server, maintenance-free design. No Windows server and database server required, unlimited mail accounts, storage, attachment size, custom logo. Free for commercial use.
China
Sanwhole Exchange is a server running iMail, iPress and iStore services. iMail is an enterprise-class email server does Microsoft Exchange and Gmail work. iPress sets blog, forums and tickets in one. iStore is an online store.
China
Xeams is a secure and powerful mail server for that includes a powerful spam filtering engine that eliminates up to 99% of junk email right out of the box. The software offers a flexible approach to email, making it a very user friendly server.
Simple, easy and secure mail server with a convenient and simple interface. Automatic certificate renewal through Let’s encrypt. Redirect, local storage. IMAP and SMTP.
Mox is a modern full-featured open source secure mail server for low-maintenance self-hosted email.
WildDuck is a scalable no-SPOF IMAP/POP3 mail server. WildDuck uses a distributed database (sharded + replicated MongoDB) as a backend for storing all data, including emails.
