AI spam filter for Apple Mail.

Name: Klar
Author: Klar

Private, secure and on your Mac.

Free forever · No account · macOS 14+ · Apple Silicon

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A year of stolen attention.

23 minutes to refocus after one interruption, per Gloria Mark's research at UC Irvine (2008).
Multiplied by 365 days, that's 17 workdays a year.

A year of stolen attention.

23 minutes to refocus after one interruption, per Gloria Mark's research at UC Irvine (2008).
Multiplied by 365 days, that's 17 workdays a year.

Klar works inside the Mail app you already use.

Junk 8 messages · Sorted by Klar

Amaz0n Security 09:14

Unusual sign-in activity detected

We noticed a login from a new device. Verify your account within 24 hours…

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1 Message

Amaz0n Security To: you@icloud.com

09:14

Unusual sign-in activity detected

We noticed a sign-in to your account from a new device in another country. If this was not you, confirm your identity within 24 hours or your account will be locked. Verify your details here…

Klar's dashboard showing active on-device inbox protection

100+: languages
Instant: filtering
100%: on-device

How it works

You install it

Install from the App Store and switch it on in Mail. No account, no cloud, nothing to configure.
It filters on arrival

Klar checks each message the moment it arrives and moves spam and phishing to Junk. Automatically, in the background.
You stay in control

Three sensitivity levels, from Cautious to Aggressive. Spam is moved to Junk, never deleted, so nothing is lost.

One model, on your Mac.

Type or paste any email. Klar sorts it into Inbox, Marketing, or Junk, like it would in Mail.

New Message from any app

To you@example.com

Subject

Drop real emails here, or click to upload .eml files

No inspiration? Try one:

Your Apple Mail

Inbox 3 messages · Sorted by Klar

Your own AI, with Klar Plus.

Drag a message where it belongs. The model learns from that correction, on your Mac.

Every verdict listed, with how sure it was
Corrections land within the minute, not overnight
The model stays on your Mac, and it is yours alone

Klar Plus is an optional add-on, coming soon.

See Klar Plus

The Klar Plus classifications view: each email listed with its verdict and confidence

Private and accurate.

Cloud filters read your mail on their servers. Traditional filters that stay on your Mac keep it private, but rely on simpler techniques. Klar runs a modern multilingual AI model on your Mac, in over 100 languages. Your mail is not uploaded for classification. A report leaves only when you send its editable draft yourself.

Private by architecture, not by promise.

The part of Klar that reads your inbox has no network access at all. It cannot send your mail anywhere, because it has nowhere to send it. Your mail is filtered on your Mac, never on a server. We are based in the EU, and the few things we do host, like this website, run on EU servers.

Made in EU

Private and smart. Choose both.

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

For the nerds

Model: XLM-RoBERTa, trained for spam detection.
Speed: 13 to 44 ms per message on an M1 Pro, on the Mac's own GPU. A 382 MB classifier inside the app, not a chat model behind an API call.
Languages: 100+, detected automatically.
Privacy: No network entitlement. It cannot phone home.
Categories: Spam, regular mail, marketing, gibberish.
Control: Three profiles: Cautious, Standard, Aggressive.

The long versions Read the BERT series How to check what a Mac app can do The engine on GitHub

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. Klar checks mail in the background, so Mail stays fast. Checking a message takes a few hundredths of a second.

Does Klar send my emails to a server?

Not automatically. Classification runs on your Mac, and the app and extension have no network access. If you choose Email report, Klar opens a draft in your mail app. It may include the selected original and a removable summary of the previous month’s local usage totals. You review, edit and send it yourself. See our Privacy Policy.

Which languages are supported?

100+ languages out of the box. Klar detects the language itself, with nothing to set up.

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.

Should I turn off Apple Mail’s own junk filter?

Yes, for the cleanest results. Open Mail → Settings → Junk Mail and turn off Enable junk mail filtering. Klar is then your only inbox filter, so two filters cannot disagree. This only changes your Mac. Mail that your provider already moved to Junk on its own servers stays there.

Is Klar free?

Yes. Klar’s spam filtering is free and stays free. Klar Plus is an optional paid companion that adds a dedicated Marketing folder and learns from your corrections.