A private alternative to SpamAssassin

Klar filters spam on your Mac, inside Apple Mail. No account, no cloud, nothing to hand over.

Download on the App Store

If you are weighing up SpamAssassin, here is how Klar differs and where each one is the better pick.

AspectKlarSpamAssassin
Runs onYour MacYour mail server
Who can read your mailNo one new during filtering. Classification stays on your device.Runs on your own server. Mail stays on your infrastructure.
Works withApple Mail, with any account: IMAP, Gmail, iCloud, ExchangeServer-side, in front of any mailbox (Postfix, Sendmail and other MTAs)
PriceFree foreverFree and open source

Klar fits better when You read mail in Apple Mail and don't run your own mail server

The honest picks

SpamAssassin
The classic open-source filter: rules plus Bayesian scoring, two decades of deployment. Powerful once tuned, but it lives on a mail server you run and maintain, not on your Mac. For a lightweight self-hosted layer, see Klar Pro.
Klar
Pick Klar if you read mail in Apple Mail and want a modern multilingual model that runs entirely on your Mac. No account, no cloud, nothing to hand over.

Product and price details from the vendors' public pages, July and August 2026: spamassassin.apache.org. Klar is not affiliated with any vendor named here. No vendor endorses Klar. Product names only identify the tools.

See the full Klar vs SpamAssassin comparison

Reclaim your inbox

Spam filter for Apple Mail. Free on the App Store.

Download on the App Store