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harper

From public sources

Offline, privacy-first grammar checker. Fast, open-source, Rust-powered

CLI toolCategory: Developer Tools · Documentation tools · Editors & IDEsOpen sourcedata checked Oct 16, 2026
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Overview

  • chrome-extension
  • developer-tools
  • english-language
  • grammar-checker
  • nodejs
  • react
  • rust
  • svelte
  • webassembly

Installation

Commands are shown, never run by the marketplace. Check them against the official documentation.

Compatibility

Unknown means no evidence was found — not that the product is incompatible.
PlatformStatusArchitectureEvidenceConfidence
WindowsCompatiblex86_64official build in release v3.0.0: harper-cli-x86_64-pc-windows-msvc.zip0.70
Compatiblearm64official build in release v3.0.0: harper-win32-arm64-3.0.0.vsix0.70
macOSCompatiblearm64official build in release v3.0.0: harper-cli-aarch64-apple-darwin.tar.gz0.70
Compatiblex86_64official build in release v3.0.0: harper-cli-x86_64-apple-darwin.tar.gz0.70
Compatible—official build in release v3.0.0: Harper.app.tar.gz0.60
Compatibleuniversalofficial build in release v3.0.0: Harper_3.0.0_universal.dmg0.70
LinuxCompatiblearm64official build in release v3.0.0: harper-cli-aarch64-unknown-linux-gnu.tar.gz0.70
Compatiblex86_64official build in release v3.0.0: harper-cli-x86_64-unknown-linux-gnu.tar.gz0.70
Compatiblearmv7official build in release v3.0.0: harper-linux-armhf-3.0.0.vsix0.70
Container (OCI)Unknown———

Releases

checked Oct 30, 2026
v3.0.0LatestOct 27, 2026Official source ↗

Files in 3.0.0

The marketplace does not host these files: downloads go to the official source. Files have not been scanned by us.
FilePlatformSizeSHA-256Download from the official source
Harper.app.tar.gzmacos · app_bundle51.2 MB9bbd0e976398…Official source ↗
Harper_3.0.0_universal.dmgmacos · universal · dmg50.6 MBcefc5eef2b69…Official source ↗
Harper_3.0.0_x64-setup.exewindows · x86_64 · exe22.9 MB78d79e9041fb…Official source ↗
harper-alpine-arm64-3.0.0.vsixUnknown13.9 MBad615afc7ea3…Official source ↗
harper-alpine-x64-3.0.0.vsixUnknown14.4 MBc678a27f9fbd…Official source ↗
harper-chrome-plugin.zipUnknown8.1 MB165e9fad3b58…Official source ↗
harper-cli-aarch64-apple-darwin.tar.gzmacos · arm64 · tarball12.2 MB77fd28bbfcf1…Official source ↗
harper-cli-aarch64-unknown-linux-gnu.tar.gzlinux · arm64 · tarball12.4 MB5b583c04ffcb…Official source ↗
harper-cli-aarch64-unknown-linux-musl.tar.gzlinux · arm64 · tarball12.4 MB9a29e026662b…Official source ↗
harper-cli-x86_64-apple-darwin.tar.gzmacos · x86_64 · tarball12.3 MB0dafa04788ea…Official source ↗
harper-cli-x86_64-pc-windows-msvc.zipwindows · x86_64 · zip11.9 MB741c3beefe21…Official source ↗
harper-cli-x86_64-unknown-linux-gnu.tar.gzlinux · x86_64 · tarball12.8 MBd136a76d75cf…Official source ↗
harper-cli-x86_64-unknown-linux-musl.tar.gzlinux · x86_64 · tarball12.8 MBfb15a5a2deed…Official source ↗
harper-darwin-arm64-3.0.0.vsixmacos · arm64 · vsix13.7 MB6081e13855f5…Official source ↗
harper-darwin-x64-3.0.0.vsixmacos · x86_64 · vsix13.7 MB09a3bb889c7e…Official source ↗
harper-firefox-plugin.zipUnknown8.1 MBf8cc12dd9450…Official source ↗
harper-linux-arm64-3.0.0.vsixlinux · arm64 · vsix13.9 MB99d023064afd…Official source ↗
harper-linux-armhf-3.0.0.vsixlinux · armv7 · vsix14 MB0b8d00b4577b…Official source ↗
harper-linux-x64-3.0.0.vsixlinux · x86_64 · vsix14.3 MB77efc32d5084…Official source ↗
harper-ls-aarch64-apple-darwin.tar.gzmacos · arm64 · tarball13.2 MB6ac790c9cacd…Official source ↗
harper-ls-aarch64-unknown-linux-gnu.tar.gzlinux · arm64 · tarball13.5 MB374a7a267a3c…Official source ↗
harper-ls-aarch64-unknown-linux-musl.tar.gzlinux · arm64 · tarball13.5 MBe4472152f65a…Official source ↗
harper-ls-x86_64-apple-darwin.tar.gzmacos · x86_64 · tarball13.3 MB5383a42ed483…Official source ↗
harper-ls-x86_64-pc-windows-msvc.zipwindows · x86_64 · zip13 MB5300b6317890…Official source ↗
harper-ls-x86_64-unknown-linux-gnu.tar.gzlinux · x86_64 · tarball13.9 MB17fd8dfea277…Official source ↗
harper-ls-x86_64-unknown-linux-musl.tar.gzlinux · x86_64 · tarball14 MBce62e5a37d00…Official source ↗
harper-win32-arm64-3.0.0.vsixwindows · arm64 · vsix13.3 MB7031c15b56c8…Official source ↗
harper-win32-x64-3.0.0.vsixwindows · x86_64 · vsix13.7 MB4d164442bc45…Official source ↗
harper.zipUnknown9.5 MB0a9b3b802afc…Official source ↗
Harper.app.tar.gz.sigsignature404 Bb7d35da13321…Official source ↗

Release history

Quality profile

algorithm quality-v1.0 · assessed Oct 16, 2026
Quality Score86
Risk Score0
Confidence 1.00
Quality Score and Risk Score are different measures. A high score does not guarantee safety.

Score components

Maintenance · 2020
last activity 0 days ago
Documentation · 1515
README 3884 chars, description present
Ready to use · 156
install instructions: no; releases: yes
Metadata · 1010
4/4 of description, homepage, license, topics
Releases · 1010
10 release(s), latest 14 days ago
Category confidence · 105
classifier confidence 0.5
Adoption · 1010
16450 stars (log-dampened, 10k = max)
License clarity · 55
SPDX Apache-2.0
Community · 55
issues enabled, 739 forks

License

Apache-2.0
Known licensefrom the repository host

This is the catalog policy status, not legal advice.

Sources

github.com/Automattic/harperPrimary★ 16,450 starslast activity Oct 15, 2026Primary repository · Confidence 1.00

Reviews

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README

From Automattic/harper · license Apache-2.0 · fetched Oct 30, 2026

[Harper Binaries] [Website] [Checks] [Crates.io] [NPM Version] [Downloads] [Obsidian Plugin Downloads]

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 created Harper: it is the grammar checker that fits my needs. Not only does it take milliseconds to lint a document, take less than 1/50th of LanguageTool's memory footprint, but it is also completely private.

Harper is even small enough to load via WebAssembly.

Language Support

Harper currently only supports English, but the core is extensible to support other languages, so we welcome contributions that allow for other language support.

Performance Issues

We consider long lint times bugs. If you encounter any significant performance issues, please create an issue on the topic.

If you find a fix to any performance issue, we would appreciate the contribution. Just please make sure to read our contribution guidelines first.

Links

Huge Thanks

This project would not be possible without the hard work from those who contribute.

Harper's logo was designed by Lukas Werner.

Open the repository ↗