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Software · Security & privacy

klorn

Email attention firewall. Five lanes, a reason on every message, your own model key. AGPL-3.0.

  • Completely free
  • Windows and macOS
  • Open source
  • No account

Overview

klorn is a firewall, available on Windows and macOS.

Features described in its GitHub repository and on its official website: self-hosting on your own server.

Overview written by LicitPro from the documentation published by the authors and the cited sources; we have not tried the resource ourselves.

Excerpts that establish this information
  • “Email attention firewall.” — GitHub, 10 November 2026
  • “Open source, self-hostable” — official website, 10 November 2026

At a glance

All of klorn is free: no feature is locked behind a paid plan, and its code is open.

Its licence (AGPL-3.0) is a copyleft open source licence: you may use, study, modify and redistribute it, including commercially; modified versions must keep the same licence.

Strengths

  • Open source code
  • No account needed
  • Commercial use allowed

Sources and checks

  • Facts collected from GitHub (credit card, account, source code, publisher, licence, free status, platforms, commercial use) —
  • Last technical check: 10 November 2026
  • Description from github.com — Dépôt GitHub k08200/klorn (AGPL-3.0-only)

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