2 Best Open Source Grammarly Alternatives
A curated collection of the 2 best open source and self-hosted alternatives to Grammarly in 2026.
Looking for a free, privacy-friendly, or self-hosted replacement for Grammarly in 2026? The top open-source alternative is Harper — Open source grammar checker that analyzes your writing quickly while keeping your data completely private and secure on your device..
Other highly rated open-source Grammarly alternatives include LanguageTool.
Open source grammar checker that analyzes your writing quickly while keeping your data completely private and secure on your device.
Open source grammar checker that analyzes your writing quickly while keeping your data completely private and secure on your device.
AI-powered grammar and style checker
LanguageTool is an AI-based writing assistant that helps you correct grammar, spelling, and style mistakes in real-time. Whether you're drafting an email, writing a document, or creating content, LanguageTool ensures your text is polished and professional. - Grammar & Spelling Check: Detects and corrects grammar, punctuation, and spelling errors across 30+ languages. - Style & Tone Suggestions: Provides recommendations to improve clarity, conciseness, and readability. - Paraphrasing Tool: Rewrites sentences to enhance originality and avoid plagiarism. - Browser & App Integrations: Available as extensions for Chrome, Edge, Firefox, Safari, and Opera, as well as plugins for Microsoft Word, Google Docs, and email clients. - Picky Mode: Advanced suggestions for perfectionists, including long sentence detection and colloquialism recognition. - Statistics & Insights: Tracks writing patterns and provides detailed analytics on text quality. - API Access: Integrate LanguageTool’s proofreading capabilities into your own applications. LanguageTool is primarily a cloud-based service, but it also offers a self-hosted version for businesses and enterprises. The self-hosted solution ensures data privacy and compliance with GDPR and other regulations. The open-source core is available on GitHub, allowing for customization and self-hosting for advanced users.
About Grammarly
AI-powered writing assistant that checks grammar, spelling, punctuation, and style to help you write clear, mistake-free content across all platforms.