head to head · open source
Avalonia vs Harper
Avalonia has 31,517 GitHub stars, 2,826 forks, 1,875 open issues and last shipped yesterday. Harper has 15,469 stars, 632 forks, 896 open issues and last shipped yesterday. Avalonia leads on adoption by 104% (31,517 vs 15,469 stars). Avalonia is written in C# under MIT; Harper is written in Rust under Apache-2.0. Avalonia has attracted 9% as many forks as stars, Harper 4%. Avalonia 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
| Avalonia | Harper | |
|---|---|---|
| GitHub stars | ★ 32K | ★ 15K |
| License | MIT | Apache-2.0 |
| Written in | C# | Rust |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 2.8K | ⑂ 632 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Avalonia if
- You weight community size — 32K stars and counting
- You want the MIT 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 Avalonia
Avalonia is a cross platform UI framework for .NET, written in C and driven by XAML. It provides a flexible styling system and targets a wide range of platforms, including Windows, macOS, Linux, iOS, Android and WebAssembly. The project is mature and production ready, and it is used by companies such as Schneider Electric, Unity, JetBrains and GitHub. It lives in the .NET ecosystem and is distributed through the NuGet package manager.
read the full Avalonia 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 Avalonia or Harper more popular?
Avalonia has 31,517 GitHub stars and Harper has 15,469. Avalonia has the larger community by that measure.
Are Avalonia and Harper free?
Both are open source. Avalonia is licensed under MIT and Harper under Apache-2.0. Neither carries a licence fee.
What is the difference between Avalonia and Harper?
Avalonia 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, Avalonia or Harper?
Choose Avalonia if you want the larger community (31,517 stars) or its MIT licence terms. Choose Harper if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.