head to head · open source
serenity vs Harper
serenity has 33,840 GitHub stars, 3,541 forks, 739 open issues and last shipped yesterday. Harper has 15,469 stars, 632 forks, 896 open issues and last shipped yesterday. serenity leads on adoption by 119% (33,840 vs 15,469 stars). serenity is written in C++ under BSD-2-Clause; Harper is written in Rust under Apache-2.0. serenity has attracted 10% as many forks as stars, Harper 4%. 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.
← all 8884 open source comparisons
Side by side
| serenity | Harper | |
|---|---|---|
| GitHub stars | ★ 34K | ★ 15K |
| License | BSD-2-Clause | Apache-2.0 |
| Written in | C++ | Rust |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 3.5K | ⑂ 632 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick serenity if
- You weight community size — 34K stars and counting
- You want the BSD-2-Clause license terms
- Your stack matches C++
- 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 serenity
SerenityOS is a graphical Unix like operating system built for 64 bit x86, Arm, and RISC V computers. It is written in C++ and released under the BSD 2 Clause license, and it lives in the open source operating system ecosystem alongside other hobbyist and research kernels. The project describes itself as a love letter to 1990s user interfaces paired with a custom Unix like core, aiming for a marriage between the aesthetic of late 1990s productivity software and the power user accessibility of late 2000s Unix systems.
read the full serenity 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 →
More in Productivity & Utilities
Related comparisons
More Browsers & Extensions projects
Compare either of these against the rest of the Browsers & Extensions field.
Frequently asked questions
Is serenity or Harper more popular?
serenity has 33,840 GitHub stars and Harper has 15,469. serenity has the larger community by that measure.
Are serenity and Harper free?
Both are open source. serenity is licensed under BSD-2-Clause and Harper under Apache-2.0. Neither carries a licence fee.
What is the difference between serenity and Harper?
serenity is written in C++ 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, serenity or Harper?
Choose serenity if you want the larger community (33,840 stars) or its BSD-2-Clause licence terms. Choose Harper if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.