GNU IceCat
The GNU project's all-free Firefox.
Firefox rebuilt to be 100% free software: no proprietary blobs, LibreJS blocks non-free JavaScript, privacy patches applied. Ideologically pure, practically niche.
- Engine
- Gecko
- License
- Open source
- Runs on
- Linux
- Top marks
- Tracking protection, Open source, Independence
- Updated
- September 2026
Why it shines
- Strictly free software, top to bottom
- LibreJS and privacy extensions included
Worth knowing
- Releases lag far behind Firefox — a real security concern
- LibreJS breaks much of the modern web
Origins
GNU IceCat belongs to The Mozilla family — descended from Firefox.
Scorecard
- Tracking protection3/3
- Fingerprinting resistance0/3
- Anonymity0/3
- Built-in ad blocking2/3
- Customization0/3
- Keyboard control0/3
- Built-in tools0/3
- Minimal interface0/3
- Fresh design0/3
- Classic interface0/3
- Light on resources1/3
- Raw speed0/3
- Battery efficiency0/3
- Extension ecosystem2/3
- Cross-device sync0/3
- Site compatibility1/3
- Low maintenance0/3
- Open source3/3
- Independence3/3
- Built-in AI0/3
- Gaming features0/3
- Dev tooling0/3
0–3 on each of the 22 criteria the quiz and the guides rank by. How we score.
