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Postfix vs Haraka: catalog facts
Postfix	Haraka
Free Free and open source.	Free Free open-source software.
macOS, Linux, Self-hosted	Linux, Self-hosted, Command line
Security-focused design Runs on many Unix-like systems	High performance SMTP handling Flexible plugin system in JavaScript
Transfer agent only; needs a separate IMAP server for mailboxes Configuration requires mail server knowledge	Handles SMTP only; needs other software for mailbox access Customisation requires JavaScript knowledge
Self-hosted	Downloadable app, Self-hosted
Open source	Open source
License not stated	License not stated
No account needed	No account needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked September 24, 2026	Official website Full listing and sources Checked October 1, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.