Compare software

Postal vs Stalwart: catalog facts
Postal	Stalwart
Free Free and open source to run on your own server.	Free Free and open source, self-hosted.
Self-hosted	Linux, Self-hosted
Self-hosted alternative to hosted transactional email services Handles both sending and receiving mail	Modern JMAP support alongside traditional IMAP and SMTP protocols Rust implementation aims for security and performance
Requires running and maintaining your own mail server Deliverability depends on your own server reputation and setup	Requires self-hosting and server administration knowledge Newer project with a smaller ecosystem than long-established mail servers
Self-hosted	Self-hosted
Open source	Open source
License not stated	License not stated
No account needed	Not stated if an account is needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked September 22, 2026

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