AI spam filter for Apple Mail
Keep spam out of Apple Mail.
Catches the spam that slips through.
100% on your Mac. Never in the cloud.
Every email checked, right on your Mac
- 100+
- languages
- Instant
- filtering
- 100%
- on-device
Accuracy and privacy
Everyone trades accuracy for privacy. Klar refuses to.
Cloud filters are accurate because they read your mail on their servers. On-device filters stay private but basic. Klar runs a modern multilingual transformer, cloud-grade AI, entirely on your Mac. Both, finally.
Where Klar fits
| Category | Where your mail is read | The intelligence |
|---|---|---|
| Cloud filters | On their servers | Large models, trained on everyone's mail |
| Classic Mac filters | On your Mac | Word statistics you train yourself |
| Klar | On your Mac | A modern multilingual AI model |
See the full comparison: SaneBox, SpamSieve, Gmail, Microsoft 365, Libraesva
Private by design
Private by architecture, not by promise.
The part of Klar that reads your inbox has no network access at all. By construction, it cannot send your mail anywhere: it is filtered on your Mac, never on a server. Built and based in the EU, and the only things we host, like this website, run on EU servers.
How it works
- 01
Install
Install from the App Store, switch it on in Mail. No account, no cloud, no setup.
- 02
Every email, checked
Klar checks each message the moment it arrives and moves spam and phishing to Junk. Automatically, in the background.
- 03
It learns from you, with Klar Plus
Correct a mistake and Klar Plus retrains the filter on your own mail, entirely on-device. See Klar Plus
What’s under the hood
- Model
- XLM-RoBERTa, a 550M-parameter multilingual transformer, paired with a fast on-device classifier that learns your inbox.
- Speed
- Two-stage pipeline. A pre-filter handles obvious cases instantly; the neural model classifies the ambiguous rest.
- Languages
- 100+ languages supported natively. No configuration needed. The model detects the language automatically.
- Privacy
- Every email is classified on your Mac. Nothing is sent to a server. No cloud, no API calls, no telemetry.
- Learning
- Learns instantly. Every correction updates the model on the spot, on-device. A nightly pass re-checks older mail so your first days stay fast.
- Accuracy
- Classifies into 4 categories (spam, ham, marketing, gibberish) with three sensitivity profiles you control (Cautious, Standard, Aggressive).
Frequently asked
How do I check Klar is registered in Apple Mail?
Two ways. In Mail, open Settings → Extensions. Klar should be in the list with its checkbox ticked. Or from Terminal: pluginkit -m -i im.klar.Klar.KlarMailExtension. A leading + means the extension is registered and enabled.
Which mail accounts does it work with?
Anything Apple Mail reads: iCloud, Gmail, Fastmail, Outlook, custom IMAP. Klar classifies the messages Mail shows you, regardless of provider.
Does it slow Mail down?
No. A pre-filter handles obvious cases instantly; only ambiguous mail reaches the neural model, and classification runs asynchronously, so Mail stays responsive.
Does Klar send my emails to a server?
No. The model runs on your Mac. No cloud, no API calls, no telemetry. See our Privacy Policy.
Which languages are supported?
100+ languages out of the box. The model detects the language automatically. No configuration.
What if Klar misclassifies a message?
Drag it back (Junk → Inbox or Inbox → Junk) and the message moves to the right folder. With Klar Plus, that correction retrains the filter and a nightly pass re-checks older mail, so the next similar message lands where it should.
Reclaim your inbox
Spam filter for Apple Mail. Free on the App Store.
Requires macOS 14 Sonoma or later.