head to head · open source
uBlock vs Harper
uBlock has 69,033 GitHub stars, 4,427 forks, 15 open issues and last shipped yesterday. Harper has 17,365 stars, 794 forks, 896 open issues and last shipped yesterday. uBlock leads on adoption by 298% (69,033 vs 17,365 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 5%. Harper 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 | ★ 69K | ★ 17K |
| License | GPL-3.0 | Apache-2.0 |
| Written in | JavaScript | Rust |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 4.4K | ⑂ 794 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick uBlock if
- You weight community size — 69K 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
[![Badge Commits]][Commit Rate] [![Badge Issues]][Issues] [![Badge Localization]][Crowdin] [![Badge License]][License] [![Badge NPM]][NPM] [![Badge Mozilla]][Mozilla] ![Badge Chrome] [![Badge Edge]][Edge] uBlock Origin (uBO) GitHub Releases Stable and development versions on Firefox, Chromium MV2, and Thunderbird. Must be placed manually into web browsers; the Chromium and Thunderbird versions usually won't auto update. Related: uBlock Origin Lite uBlock Origin (uBO) is a CPU and memory efficient [wide spectrum content blocker][Blocking] for Chromium and Firefox. It blocks ads, trackers, coin miners, popups…
read the full uBlock overview →
About Harper
Harper Harper is an English grammar checker designed to be just right. I created it after years of dealing with the shortcomings of the competition. Grammarly was too expensive and too overbearing. Its suggestions lacked context, and were often just plain wrong . Not to mention: it's a privacy nightmare. Everything you write with Grammarly is sent to their servers. Their privacy policy claims they don't sell the data, but that doesn't mean they don't use it to train large language models and god knows what else. Not only that, but the round trip time of the network request makes revising your work all the more…
read the full Harper overview →
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Frequently asked questions
Is uBlock or Harper more popular?
uBlock has 69,033 GitHub stars and Harper has 17,365. 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 (69,033 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.