head to head · open source
uBlock vs Zen Browser
uBlock has 67,923 GitHub stars, 4,353 forks, 15 open issues and last shipped yesterday. Zen Browser has 44,481 stars, 1,754 forks, 689 open issues and last shipped yesterday. uBlock leads on adoption by 53% (67,923 vs 44,481 stars). uBlock is written in JavaScript under GPL-3.0; Zen Browser is written in C++ under MPL-2.0. uBlock has attracted 6% as many forks as stars, Zen Browser 4%. Zen Browser was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (firefox), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| uBlock | Zen Browser | |
|---|---|---|
| GitHub stars | ★ 68K | ★ 44K |
| License | GPL-3.0 | MPL-2.0 |
| Written in | JavaScript | C++ |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 4.4K | ⑂ 1.8K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick uBlock if
- You weight community size — 68K stars and counting
- You want the GPL-3.0 license terms
- Your stack matches JavaScript
- You value the larger contributor base for long-term maintenance
pick Zen Browser if
- You want the Zen Browser feature set and don't need the biggest community
- You prefer the MPL-2.0 license terms
- Your stack matches C++
- You evaluated both and Zen Browser fits your workflow better
About uBlock
uBlock Origin is a CPU and memory efficient, wide spectrum content blocker for Chromium and Firefox, aimed at anyone who wants ads, trackers, coin miners, popups, anti blockers and malware sites neutralised by default without hand tuning anything.
read the full uBlock overview →
About Zen Browser
Zen Browser is a privacy focused, open source web browser built on Firefox’s Gecko engine. It inherits Firefox’s compatibility and extension ecosystem while introducing a streamlined interface and productivity oriented features. The project lives in the desktop browser ecosystem, targeting users who want a Firefox based experience with reduced clutter and enhanced customization.
read the full Zen Browser overview →
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Frequently asked questions
Is uBlock or Zen Browser more popular?
uBlock has 67,923 GitHub stars and Zen Browser has 44,481. uBlock has the larger community by that measure.
Are uBlock and Zen Browser free?
Both are open source. uBlock is licensed under GPL-3.0 and Zen Browser under MPL-2.0. Neither carries a licence fee.
What is the difference between uBlock and Zen Browser?
uBlock is written in JavaScript and Zen Browser in C++. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, uBlock or Zen Browser?
Choose uBlock if you want the larger community (67,923 stars) or its GPL-3.0 licence terms. Choose Zen Browser if its feature set, stack or MPL-2.0 licence fits better. Both are self-hostable.