Privacy Policy

Last updated: August 2026

Summary

Klar processes your email on your Mac. The free App Store app and Mail extension have no network access and send no automatic telemetry. Klar Plus has network access for licences, app updates and model updates, but none of those requests carries your mail. Plus keeps a bounded local copy of messages it classifies so previews, corrections, later model versions and spam deleted by the provider remain usable. Nothing in that corpus is transmitted automatically. If you choose Email report, Klar opens an editable draft in your own mail app. It may contain the selected original messages, classification diagnostics and a removable summary of the previous calendar month’s local usage totals, and you decide whether to edit or send it. The classifier demo and newsletter on this website are separate and are described below.

What Klar Does

Klar is a spam filter for Apple Mail that runs as a native Mail extension on macOS. When you receive an email, Klar’s machine learning model analyzes it locally on your device to determine whether it is spam. The classification result is used by Mail to move spam to your Junk folder.

Data We Collect

Nothing automatically.

  • Emails handled by the app are processed on-device and never sent automatically. Only messages you deliberately include in an Email report leave your Mac.
  • The ML model runs locally. No cloud API calls are made during classification.
  • We collect no automatic usage analytics, crash reports or telemetry. A user-sent Email report includes a visible, removable summary with the previous month, emails checked, unwanted messages caught, messages moved to Junk, a completeness flag and a random identifier used only to deduplicate that month’s reports and honor deletion requests. A different unrelated identifier is generated for every month.
  • We do not use advertising or analytics cookies. The optional support chat sets a functional cookie so a conversation stays linked to you (see “Support Chat” below).
  • We run no advertising or analytics tracking scripts. The footer carries one ad slot, part of an exchange between small independent sites (ad-swap.web.app), which cycles through the products in the exchange. It loads in a sandboxed frame that cannot keep an identifier for you, and we receive nothing about you from it. Each product’s logo is loaded from that product’s own server, so those servers, and ad-swap itself, see the IP address and browser of visitors whose browser loads the slot, as any site you open does.

The demo on this website

The classifier demo on klar.im is not the app. It runs the same model on our server in France, so whatever you paste or drop into it is sent to us to be scored. Scoring is not storing: the message is classified and discarded, and we keep no copy.

  • If you press the thumbs up or thumbs down button under a result, that message is stored, along with the verdict you disagreed or agreed with. That button is the only thing that stores anything, and it is never pressed for you.
  • A stored report keeps no IP address, no cookie and no account. We cannot tell which reports are yours.
  • Your browser keeps a token for each report you send, so you can delete it from the same browser. Reports are deleted automatically after 180 days in any case.
  • Do not paste anything you would not want us to read. Use the demo with a message you are comfortable sharing.
  • The demo never loads remote images from a message you test, and shows how many it blocked. A tracking pixel in spam is how a sender learns a real person opened it, so loading one would tell the spammer about you. HTML messages render in a locked-down frame with scripts and network access switched off.

Data Storage

Klar stores the following data locally on your Mac in a sandboxed App Group container:

  • Classification database: A local SQLite database recording which emails were classified and the result. This avoids re-classifying emails and supports the correction workflow. It stays on your device. If you send an Email report, Klar derives the removable monthly totals shown in its draft from this database.
  • ML model files: The spam classification model, stored in the shared App Group container so both the extension and the app can access it.
  • User preferences: Your filtering sensitivity, spam action preference, and contacts whitelist setting, stored in shared UserDefaults.
  • Klar Plus message corpus: One LZFSE-compressed RFC822 source for each message Plus classifies, capped at 2 GiB in the App Group. Messages up to 10 MiB keep their full source; larger messages keep a versioned replay source without attachment payloads. When the cap is reached, ordinary messages are evicted before disagreements, confirmed spam and explicit corrections. Metadata and prediction history can remain after the source is evicted. This storage is local Plus functionality, not an upload queue.

Contacts Access

Klar can optionally access your macOS Contacts to whitelist emails from people you know. Contact email addresses are synced to a local database only. They are never transmitted off your device. You can disable this feature at any time in the app settings.

Network Access

The App Store version of Klar makes no network requests. Klar Plus uses the network to check its licence, download model updates and check for app updates; none carries your mail. Its optional contribution setting sends only privacy-scrubbed derived feature bags, never raw originals. Classification and the bounded message corpus stay on your Mac.

Klar for Messages (iOS)

Klar for Messages filters texts from unknown senders on your iPhone. By default everything happens on-device: the message text never leaves your phone. The app also offers an optional cloud check. It is off by default and you can switch it on or off in the app at any time.

  • If you turn the cloud check on, iOS itself sends the sender and the text of messages from unknown senders to klar.im. The app has no network access of its own.
  • On arrival we reduce both values to irreversible digests: a keyed hash of the sender and a similarity hash of the text. The phone number, the message text, and your IP address are never stored.
  • There is no account and no device identifier. Nothing in this data can be tied to you or to your phone.
  • Every record expires after 30 days. Switching the cloud check off stops all requests immediately.

The cloud check exists to spot campaigns: the same scam text arriving from many different numbers at once. That is the one signal an on-device filter cannot see.

Third-Party Services

The App Store version of Klar integrates with no third-party service and makes no network requests. If you send an Email report, your chosen mail provider delivers it just like any email you write.

Children’s Privacy

Klar collects no personal information automatically from anyone, including children under 13. Email reports are sent only after the user reviews and sends a draft in their own mail app. Our newsletter is meant for adults. If you believe a child has sent information or subscribed, write to <a href="mailto:contact@crisp.klar.im">contact@crisp.klar.im</a> and we will delete it.

GDPR Compliance

Klar is made in the European Union and designed with privacy as a core principle. We have no access to your inbox. If you send an Email report, we may hold your sending address, the examples you selected, their diagnostic context and the separate monthly usage row. If you subscribe to our newsletter, we hold that address too. Your GDPR rights apply in full: write to <a href="mailto:contact@crisp.klar.im">contact@crisp.klar.im</a> to see what we hold, correct it or have it deleted. Include the Sample ID from your sent report if you want its monthly usage row deleted.

Changes to This Policy

We may update this privacy policy from time to time. Changes will be posted on this page with an updated revision date.

The Newsletter

The one thing we do store is our newsletter list, and only if you ask to be on it. When you enter your email address on this website, we keep:

  • Your email address, to send you the newsletter.
  • Your language and the page you subscribed from, so we write to you in the right language.
  • That you consented, and when, which is the record the law requires us to keep.

The legal basis is your consent. The list lives on our own server in France. We do not sell it, share it, or use it for anything else. Unsubscribe from any email we send, or write to contact@crisp.klar.im, and we delete your address.

Support Chat

Our website includes a live support chat from Crisp (Crisp IM SARL, France) so you can reach us with questions. The chat widget loads with the page and sets a functional cookie and browser identifier so a conversation stays linked to you. If you start a chat, Crisp processes the messages you send as a data processor on our behalf. We use it only for support, never for advertising or tracking. See Crisp’s privacy policy.

Contact

If you have questions about this privacy policy, contact us at contact@crisp.klar.im.