What is LanguageTool?
LanguageTool checks grammar, spelling, and style across more than 30 languages, positioning itself as a privacy-conscious, multilingual alternative to Grammarly. Its rule-based and statistical checking engine has open-source roots, and the company publishes a self-hostable version alongside its hosted product for organizations that need to keep text processing in-house.
It's built for anyone writing across multiple languages — the wide language support is the clearest differentiator versus English-first competitors — and integrates as a browser extension, desktop add-ons for Word and Google Docs, and mobile keyboards, so checking happens wherever you're already writing rather than in a separate app.
The free tier covers core grammar and spelling checks. Premium, at $9.99/month, adds more advanced style suggestions, an expanded rule set, and a plagiarism checker. An API is available for developers who want to build grammar checking into their own product.
Key Features of LanguageTool
- 30+ language support: Checks grammar and style across a much wider language set than most competitors.
- Self-hostable option: Organizations can run LanguageTool's engine on their own infrastructure for privacy.
- Browser and app integrations: Works as a browser extension, Word/Google Docs add-on, and mobile keyboard.
- API access: Integrate grammar checking directly into another product.
Use Cases for LanguageTool
- Check grammar and spelling while writing in a non-English language
- Self-host a grammar-checking engine for data-privacy requirements
- Catch style and grammar issues directly inside Word or Google Docs
- Add grammar checking to a product via API