Automattic/harper
Offline, privacy-first grammar checker. Fast, open-source, Rust-powered
From the publisher
README & documentation
Source previewRead the project’s overview, installation instructions and usage examples. The original README is the source of truth.
[](https://github.com/automattic/harper/actions/workflows/binaries.yml) [](https://github.com/automattic/harper/actions/workflows/buildweb.yml) [](https://github.com/automattic/harper/actions/workflows/justchecks.yml) [](https://crates.io/crates/harper-ls) 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 tedious. LanguageTool is great, if you have gigabytes of RAM to spare and are willing to download the 16GB n-gram dataset. Besides the memory requirements, I found LanguageTool too slow: it would take several seconds to lint even a moderate-size document. That's why I…
Read the full README ↗ · Preview checked 2026-10-27T03:29:20.357Z
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What this repository does
Offline, privacy-first grammar checker. Fast, open-source, Rust-powered
Repository facts
- Owner
- Automattic
- Primary language
- Rust
- Stars
- 17,306
- Forks
- 787
- Open issues + pull requests
- 1,007
- License
- Apache-2.0
- Archived
- No
- Default branch
- master
- Created
- 2023-10-22T02:58:35.000Z
- Last push
- 2026-10-31T11:08:34.000Z
Topics and intended use
Owner-supplied topics: chrome-extension, developer-tools, english-language, grammar-checker, nodejs, react, rust, svelte, webassembly
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Source and freshness
Source: GitHub. Metadata observed 2026-10-31T12:19:26.881Z. Daily imports are snapshots, not real-time monitoring.
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