head to head · open source
uBlock vs Harper
uBlock has 67,923 GitHub stars, 4,353 forks, 15 open issues and last shipped yesterday. Harper has 15,469 stars, 632 forks, 896 open issues and last shipped yesterday. uBlock leads on adoption by 339% (67,923 vs 15,469 stars). uBlock is written in JavaScript under GPL-3.0; Harper is written in Rust under Apache-2.0. uBlock has attracted 6% as many forks as stars, Harper 4%. uBlock was the more recently maintained of the two, and both are self-hostable with no licence fee.
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 | Harper | |
|---|---|---|
| GitHub stars | ★ 68K | ★ 15K |
| License | GPL-3.0 | Apache-2.0 |
| Written in | JavaScript | Rust |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 4.4K | ⑂ 632 |
| 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 Harper if
- You want the Harper feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Rust
- You evaluated both and Harper 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 Harper
Harper is offline, privacy first grammar checker for English. It lives in productivity, browser extension, developer tools, and text editing ecosystem. Project is open source under Apache 2.0. GitHub metadata shows 15373 stars, 627 forks, and 896 open issues. Last push is 2026 09 14. Category is Productivity & Utilities / Browsers & Extensions. It uses Rust for core, WebAssembly for browser loading, language server for editors, JavaScript package for web and Node.js apps. It solves slow, costly, network dependent grammar checking. It replaces Grammarly and LanguageTool as named in README. Grammarly sends writing …
read the full Harper overview →
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Frequently asked questions
Is uBlock or Harper more popular?
uBlock has 67,923 GitHub stars and Harper has 15,469. uBlock has the larger community by that measure.
Are uBlock and Harper free?
Both are open source. uBlock is licensed under GPL-3.0 and Harper under Apache-2.0. Neither carries a licence fee.
What is the difference between uBlock and Harper?
uBlock is written in JavaScript and Harper in Rust. 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 Harper?
Choose uBlock if you want the larger community (67,923 stars) or its GPL-3.0 licence terms. Choose Harper if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.