# Open-source alternatives to Grammarly

> Open-source alternatives to Grammarly that run locally, allow commercial use and need no paid API include Harper (grammar and spelling checks and works in the browser and other apps; Apache-2.0), Vale (style and clarity suggestions; MIT) and Lexicon (grammar and spelling checks and AI rewriting and tone changes; MIT code, Apache-2.0 weights). None of the 13 projects we track covers all 5 Grammarly jobs, so most people combine two or more.

Grammarly: Cloud writing assistant with free and paid plans that checks grammar, spelling and style, rewrites text with AI, adjusts tone, checks plagiarism and works inside browsers and desktop apps. Text is processed on Grammarly's servers. Pricing: See pricing page (checked 2026-10-15). Facts checked 2026-10-16.

## Projects

| Project | Jobs | Runs locally | Commercial use | Paid services | Hardware |
|---|---|---|---|---|---|
| [LanguageTool](https://repoquarry.dev/projects/languagetool) | grammar-spelling-check, style-clarity | Yes, as a local Java server, CLI or desktop GUI; the hosted cloud service is separate | Yes, LGPL conditions apply if you modify and distribute the core | None required to self-host; AI-based rules and Premium features are paid cloud extras | Needs Java; optional n-gram data is ~8GB and should sit on an SSD; RAM needs not documented |
| [Harper](https://repoquarry.dev/projects/harper) | grammar-spelling-check, works-everywhere | Yes, every check runs on your device | Yes, Apache-2.0 | None required | Not documented; the README claims under 1/50th of LanguageTool's memory footprint |
| [Vale](https://repoquarry.dev/projects/vale) | style-clarity | Yes, offline command-line tool | Yes, MIT | None required | Not documented |
| [textlint](https://repoquarry.dev/projects/textlint) | style-clarity | Yes, Node.js command-line tool | Yes, MIT (check each rule package's own licence) | None required | Node.js 20 or later; no other requirements documented |
| [Hunspell](https://repoquarry.dev/projects/hunspell) | grammar-spelling-check | Yes, library and command-line tool | Yes, copyleft conditions of the chosen licence apply; check each dictionary's licence | None required | Not documented |
| [proselint](https://repoquarry.dev/projects/proselint) | style-clarity | Yes, command-line tool | Yes, BSD-3-Clause | None required | Not documented |
| [Writing Tools](https://repoquarry.dev/projects/writing-tools) | ai-rewrite-tone, grammar-spelling-check, works-everywhere | Yes, desktop app; fully local only when paired with a local LLM | Yes, GPL-3.0 conditions apply if you distribute it; check your chosen model's licence | None required with a local LLM; cloud LLM APIs (free Gemini tier or paid) are optional | App itself is light; the suggested local model (Llama 3.1 8B via Ollama) needs about 8GB RAM or VRAM |
| [TeXtidote](https://repoquarry.dev/projects/textidote) | grammar-spelling-check | Yes, command-line Java tool | Yes, GPL-3.0 conditions apply if you distribute it | None required | Java 8 or later; no other requirements documented |
| [LanguageTool Integration for Obsidian](https://repoquarry.dev/projects/obsidian-languagetool) | grammar-spelling-check | Plugin runs in Obsidian; checks go to LanguageTool's cloud unless you set a self-hosted server URL | Yes, AGPL-3.0 conditions apply if you modify and distribute or host it | None required (free public API or self-hosted server); LanguageTool Premium API is optional | Not documented; a self-hosted LanguageTool server has its own needs |
| [LTeX+](https://repoquarry.dev/projects/ltex-plus) | grammar-spelling-check | Yes, offline language server; can optionally use an external LanguageTool server | Yes, MPL-2.0 and LGPL conditions apply if you modify and distribute | None required | Not documented |
| [Lexicon](https://repoquarry.dev/projects/lexicon) | grammar-spelling-check, ai-rewrite-tone | Yes, desktop app with local LanguageTool and local LLM | Yes, MIT code and Apache-2.0 model; bundled LanguageTool is LGPL | None required | RAM and CPU needs not documented; AI models are about 0.8GB (Light) or 1.4GB (Standard) |
| [OmniPoly](https://repoquarry.dev/projects/omnipoly) | grammar-spelling-check | Yes, self-hosted Docker container connected to your own backends | Yes, GPL-3.0 conditions apply if you distribute it | None required; you run LanguageTool, LibreTranslate and Ollama yourself | Not documented; depends on the LanguageTool and other backends you run |
| [write-good](https://repoquarry.dev/projects/write-good) | style-clarity | Yes, Node.js library and CLI | Yes, MIT | None required | Not documented |

## Common questions

### Is there a free, open-source alternative to Grammarly?

Yes. Writing Tools, LanguageTool, Harper, Lexicon and TeXtidote are free to download and run on your own computer without paid API keys. Each covers only part of what Grammarly does, so check which job you need.

### Can I do grammar and spelling checks locally without a Grammarly subscription?

Yes, with LanguageTool (LGPL-2.1-or-later), TeXtidote (GPL-3.0) and Writing Tools (GPL-3.0). Check the hardware notes and licence conditions on each page before you start.

### Can I do style and clarity suggestions locally without a Grammarly subscription?

Yes, with LanguageTool (LGPL-2.1-or-later), textlint (MIT) and Vale (MIT). Check the hardware notes and licence conditions on each page before you start.

### Which Grammarly alternatives can I use commercially?

Confirmed: Harper, Lexicon, proselint, textlint, Vale and write-good. With conditions: Hunspell, LanguageTool, LTeX+, LanguageTool Integration for Obsidian, OmniPoly, TeXtidote and Writing Tools. This is not legal advice; read each licence.

### Does any open-source project replace all of Grammarly?

Not as of 2026-10-16. Grammar and spelling checks, style and clarity suggestions, AI rewriting and tone changes, works in the browser and other apps and plagiarism check are covered by different projects.

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Source: RepoQuarry (https://repoquarry.dev/alternatives/grammarly). Data licence: CC BY 4.0. Quotes are from project documentation and belong to their authors.