Head to head
Klar vs SpamAssassin
What actually differs: where each filter runs, who gets to read your mail, and what it costs.
| Aspect | Klar | SpamAssassin |
|---|---|---|
| Runs on | Your Mac | Your mail server |
| Who can read your mail | No one new. Your mail never leaves the device. | Runs on your own server. Mail stays on your infrastructure. |
| Works with | Apple Mail, with any account: IMAP, Gmail, iCloud, Exchange | Server-side, in front of any mailbox (Postfix, Sendmail and other MTAs) |
| Price | Free | Free 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 for servers.
- 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 2026: c-command.com, sanebox.com, support.google.com, learn.microsoft.com, libraesva.com, spamassassin.apache.org, rspamd.com, mailinblack.com. Klar is not affiliated with or endorsed by any vendor named here; names are used only to identify the products.
The on-device option
Free, private, in Apple Mail.
