Harper: Free, Open Source Grammar Checker

Founded by Elijah Potter

The Free Grammar Checker That Respects Your Privacy

Cost

Free

Rating

★ People love it

Time to value

Immediate

You can use Harper to check grammar and spelling in your writing without sending data to external servers. This open-source grammar checker runs entirely on your device, providing instant suggestions for grammatical errors, spelling mistakes, and awkward phrasing. It works across multiple platforms including web browsers, code editors like VS Code and Neovim, note-taking apps like Obsidian, and can be integrated into websites and applications. Harper supports multiple English dialects and provides fast feedback in under 10 milliseconds since everything processes locally.

What Harper: Free, Open Source Grammar Checker does

Install browser extension for web grammar checkingSet up language server in your code editorConfigure grammar rules for your writing styleCheck spelling and grammar in real-timeReview suggested corrections for errorsIntegrate grammar checking into development workflowAdd grammar checking to web applicationsConfigure offline grammar checking for teamsRuns completely offline on your deviceProcesses grammar checks in under 10 millisecondsNever sends your data to external serversSupports multiple English dialectsAvailable as language server for code editorsWorks as browser extension for web writingIntegrates with popular note-taking appsOpen source with Apache-2.0 license

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