Self-hosted · on-prem · EU

Spam filtering for your own mail server.

The Klar engine as a Postfix / SMTP milter, running on your infrastructure. No US cloud. No mail leaves your servers.

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  1. 01

    Drops into Postfix

    Klar runs as a milter. Every inbound message is classified by the on-device engine and tagged with X-Klar headers; your Sieve rules file spam to Junk.

  2. 02

    Stays on your infrastructure

    Classification runs where your mail already lives. Nothing is sent to a third party. That is the sovereignty cloud gateways cannot offer.

  3. 03

    Learns from your users

    When users move mail to or from Junk, Klar records the correction and adapts, on your servers, not ours.

Open source · AGPLv3

Read the engine, run it yourself.

The Klar engine is open source under AGPLv3. Build it, audit it, and verify exactly what runs on your servers.

It ships with a reference Postfix milter today. A Stalwart milter is next, so the same engine drops into either mail server.

View the engine on GitHub

On the roadmap. Talk to us about a pilot.

Early access

Self-hosted Klar is rolling out to design partners. Tell us about your setup and we will be in touch.

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