Open Source Alternatives to LanguageTool

An AI-based grammar checker that identifies grammatical errors, spelling mistakes, and punctuation issues across more than 30 languages and dialects. The software provides suggestions for casing, style improvements, and semantic optimizations, and includes an AI-based paraphrasing tool to rewrite sentences for formality or conciseness. It is designed for individuals, students, and organizations to polish professional and academic content. The tool is deployed as a web-based editor, browser extensions for Chrome, Firefox, Edge, and Safari, and desktop applications for Windows and macOS. It also offers integrations for Google Docs, Microsoft Word, and LibreOffice to ensure error-free results across various writing environments. The system tracks productivity through statistics on languages used and errors corrected.

Whether you want to cut software costs or escape vendor lock-in, these open source alternatives to LanguageTool give you an option you fully own. Run them on your own server or desktop, so your data stays under your control. This page lists 1 open source alternative to LanguageTool. The most popular is Harper. It uses the Apache-2.0 license and ships an official Docker image.