LanguageTool alternatives: 4 free & open-source picks
Curated, verified, and actually free. No trials, no crippled tiers. Star counts and last-activity dates checked by hand, not scraped and forgotten.
A fast English grammar checker that stays on your device and mostly keeps its opinions to itself.
Select text anywhere, hit a hotkey, and fix, rewrite, summarize, or obey a custom instruction without opening another tab.
licenseGPL-3.0
runson your machine
installUse the portable Windows ZIP or macOS DMG; Linux currently runs from source
enginesGemini, native Ollama and any OpenAI-compatible cloud or local endpoint on Windows/Linux; the macOS port also supports OpenAI, Anthropic, Mistral, OpenRouter, Gemini, MLX and Ollama
dataAPI keys and configuration stay on the device; the app does not retain writing or logs, and selected text goes only to the chosen cloud provider unless a local model is used
the catch vs LanguageToolIt relies on generative models for corrections, so checks are less deterministic and its multilingual grammar rules and explanations are much thinner than LanguageTool's.
setupYou must supply an API key or install a local model; macOS needs Accessibility permissions, while Linux installation and Wayland support remain rough
facts verified 2026-08-14
A LibreOffice extension with long-document checks, style statistics, profiles, and local AI; installing Java is the cover charge.
licenseLGPL-2.1
runson your machine
installInstall LibreOffice 24.2+, Java 17+, then add the downloaded .oxt LibreOffice extension
enginesLanguageTool rules locally; optional AI rewriting through an OpenAI-compatible API, with local endpoints such as LocalAI specifically supported
dataChecks, profiles and cached document-analysis data run on the local computer; document text is sent away only when a remote LanguageTool or configured AI endpoint is used
the catch vs LanguageToolIts LanguageTool-based checks are strong inside LibreOffice, but browser, email, mobile, and cross-application coverage are much weaker than LanguageTool's.
setupJava 17 and a recent LibreOffice are mandatory, and users must manually install and approve the extension
facts verified 2026-08-14
Proofread, rewrite, shorten, or change tone almost anywhere, assuming your Apple hardware made the guest list.
licenseproprietary, free
runsyour machine or their cloud
installBuilt into current macOS, iOS and iPadOS; enable Apple Intelligence and let the required models download
enginesApple on-device foundation models and, for harder requests, Apple Private Cloud Compute; optional ChatGPT is used for Compose
dataEdits are applied to text in the host app rather than kept in a separate Writing Tools library; on-device requests stay local, Private Cloud Compute says request data is not stored, and optional ChatGPT receives the selected content
the catch vs LanguageToolIt is convenient on supported Apple hardware, but it covers fewer languages and gives less rule-based grammar explanation and customization than LanguageTool.
setupRequires Apple Intelligence-compatible Apple hardware, a supported language/region and several gigabytes of downloaded models
facts verified 2026-08-14
last updated 2026-08-14 · no votes, no pay-to-list · just what's real
| tool | license | running it | platforms | stars | active |
|---|---|---|---|---|---|
| Harper | open source | one-click install | macos, android, browser-extension | 14,200 | 2026-08 |
| Writing Tools | GPL-3.0 | one-click install | macos, windows | 2,400 | 2026-05 |
| WritingTool | LGPL-2.1 | one-click install | macos, windows, linux | 65 | 2026-07 |
| Apple Writing Tools | proprietary, free | one-click install | macos, ios | — | — |
They pay for hosted convenience, premium rules, and cross-device setup. If none of that applies to you, any pick above saves $65.64 a year.
Is there a free alternative to LanguageTool?
Yes: Harper, Writing Tools, WritingTool and 1 more. Every tool on this page is either open source or genuinely free to use long-term: no trials, no crippled tiers.
Should I just build my own LanguageTool?
Our verdict is SÍ. Because the core engine is open source, a technical user can run the grammar checker locally or self-host the server for many use cases. If you'd rather build, the exact one-shot prompt is free at puedovibecodearlo.app/languagetool.
