A private alternative to Postgrey
Klar filters spam on your Mac, inside Apple Mail. No account, no cloud, nothing to hand over.
If you are weighing up Postgrey, here is how Klar differs and where each one is the better pick.
| Aspect | Klar | Postgrey |
|---|---|---|
| Runs on | Your Mac | Your Postfix mail server |
| Who can read your mail | No one new during filtering. Classification stays on your device. | No new third party. It evaluates the SMTP client, sender and recipient triplet, not the message body. |
| Works with | Apple Mail, with any account: IMAP, Gmail, iCloud, Exchange | Postfix mail servers |
| Price | Free forever | Free and open source |
Klar fits better when you need content classification in Apple Mail, or you do not operate a Postfix server
The honest picks
- Postgrey
- A small, specialized server tool: defer a first delivery attempt and accept senders that retry correctly. Pick it as a low-cost greylisting layer for Postfix. It does not read message content, and greylisting can delay legitimate first-time senders. 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: postgrey.schweikert.ch. Klar is not affiliated with any vendor named here. No vendor endorses Klar. Product names only identify the tools.
Reclaim your inbox
Spam filter for Apple Mail. Free on the App Store.
