Compare software

Exim vs Postfix: catalog facts
Exim	Postfix
Free Free and open source under the GNU General Public Licence.	Free Free and open source.
Linux, Self-hosted, Command line	macOS, Linux, Self-hosted
Very flexible mail routing Extensive checks for incoming mail	Security-focused design Runs on many Unix-like systems
Configuration is complex and differs from Sendmail A mail server, not a client for reading email	Transfer agent only; needs a separate IMAP server for mailboxes Configuration requires mail server knowledge
Downloadable app, Self-hosted	Self-hosted
Open source	Open source
License: GPL	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 September 24, 2026

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