Klar: Private AI Spam Filtering for Apple Mail
Klar is a free spam filter that runs entirely on your Mac. Instead of sending your messages to a cloud service for analysis, Klar uses a modern multilingual AI model (XLM-RoBERTa) directly on your machine's GPU. Your email never leaves your computer.
How It Works
- Install and enable: Get Klar from the App Store and switch it on in Apple Mail. No account or configuration is needed.
- Automatic filtering: Klar checks each message as it arrives and moves spam, phishing, and junk to the Junk folder. It never deletes anything.
- Stay in control: Choose from three sensitivity levels — Cautious, Standard, or Aggressive — to match your preferences.
Privacy by Architecture
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. Classification happens locally, and the app is based in the EU.
Works With Your Accounts
Klar works with anything Apple Mail reads: iCloud, Gmail, Outlook, Fastmail, and custom IMAP accounts. It supports over 100 languages and detects them automatically.
Performance
Checking a message takes just 13 to 44 milliseconds on an M1 Pro, so Mail stays fast. The classifier is a 382 MB model inside the app, not a chat model behind an API call.
Optional Klar Plus
Klar Plus is a paid companion in development that adds a dedicated Marketing folder and learns from your corrections. The core spam filtering remains free forever.
For Developers and Self-Hosters
Klar also runs as a milter for Postfix and SMTP on infrastructure you control, via Klar Pro.