LanguageTool

LanguageTool is an open-source grammar and style checker supporting more than 30 languages. Its browser extensions and desktop apps catch spelling, punctuation, and style errors wherever you write.

LanguageTool checks grammar, spelling, punctuation, and style across 30-plus languages, from English to Japanese. Its open-source core stays transparent and lets developers self-host it.

It suits multilingual writers, students, and professionals wanting reliable proofreading without vendor lock-in. Extensions for Gmail, Google Docs, and WordPress bring corrections wherever you work. Check the official site for current plan details.

Key Features

Thirty-plus Language Support

Check grammar natively in over 30 languages, including French, German, Spanish, and Portuguese, not just English.

Open-Source Core

The transparent, auditable codebase can be self-hosted on your own server for complete data privacy.

Browser Extensions

Inline underlining flags errors as you type in Gmail, Google Docs, WordPress, and most websites.

Picky Mode

Premium's picky mode catches subtle stylistic issues and tricky word-choice problems that basic checks miss.

Personal Dictionary

Add names, acronyms, and technical terms so your specialized vocabulary never gets wrongly flagged again.

AI Paraphrasing

Quickly rephrase sentences with smart AI-powered suggestions, enjoying unlimited daily paraphrasing on premium plans forever.

Team Style Guides

Teams can encode preferred wording and shared dictionaries so everyone's writing stays consistent and on-brand.

Frequently Asked Questions (FAQ)

How is LanguageTool different from Grammarly?

Its open-source core and 30-plus language coverage are the biggest edges. Grammarly polishes English slightly better, but LanguageTool wins for multilingual, privacy-conscious writers everywhere. Its transparent open-source model also appeals to security-minded organizations.

Can I self-host LanguageTool?

Yes. The open-source version runs on your own server with no request limits — ideal for strict privacy needs. Self-hosting uses basic rules, while premium checks need a separate license for advanced features.

Which languages does LanguageTool support?

More than 30 languages, including English, German, French, Spanish, Dutch, Polish, Portuguese, Russian, and Japanese. Few grammar checkers match this breadth, making it a favorite for multilingual teams. Coverage grows as the open-source community contributes new language rules.

What does Picky Mode do?

Picky Mode is a premium setting applying extra-strict style rules, catching subtle redundancies and tone issues. It suits writers polishing formal documents, theses, and professional reports to a high standard.

Does LanguageTool work offline?

The desktop app offers offline checking, though the browser extension is more polished. Self-hosted setups also work fully offline, giving maximum privacy and control over your writing data. Perfect for confidential documents and sensitive professional work.

Who benefits most from LanguageTool Premium?

Writers needing advanced style rules, unlimited paraphrasing, and longer text checks gain the most. Student and educator discounts make Premium highly affordable for academic users on tight budgets. Schools and universities can equip entire classrooms affordably.

Conclusion

LanguageTool is an open and privacy-conscious grammar checker, supporting 30+ languages with an open-source core and picky mode for style control. Its extensions and desktop apps put corrections everywhere you type without editor lock-in. It lacks the AI rewriting flair of newer tools, but for accurate multilingual proofreading you can self-host and trust, it is a reliable choice.