Sure, Postfix is awesome.

But have you considered these open source alternatives?

They are free, self-hostable and community-driven.

Check by yourself:  Stalwart .

  1. So is Stalwart

    All-in-one Mail & Collaboration server

    ★ 8.6K Mail Collaboration Calendar License: AGPL-3.0

    Stalwart is an open-source mail & collaboration server with JMAP, IMAP4, POP3, SMTP, CalDAV, CardDAV and WebDAV support and a wide range of modern features. It is written in Rust and designed to be secure, fast, robust and scalable.

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