Best free Grammarly alternatives (open source, 2026)
Updated · 20 repos compared · data refreshed nightly from GitHub
The most popular free Grammarly alternative for most people is open-notebook (40k GitHub stars, MIT license). PaperForge works on a Mac according to its README. All 20 options below are open source and run on your own computer or server, so there's no subscription.
Grammarly (AI writing and grammar checks) is a paid, closed-source product. The open-source projects below do the same job and run on your own computer or server. Stars and activity come straight from GitHub.
Top picks
An Open Source implementation of Notebook LM with more flexibility and features
- Needs:
- Hardware not stated in its README
- Trade-off
- Better than Grammarly: the biggest community (40k stars), a permissive MIT license. Worse: you install and run it yourself instead of Grammarly's hosted app.
End-to-end AI-powered academic paper writing system — from idea generation and literature search to experiment execution, result backfill, and LaTeX paper compilation. Supports multi-LLM routing, SSH
- Needs:
- works on Mac (per README)
- Trade-off
- Better than Grammarly: very active development. Worse: license not detected by GitHub; check it before commercial use; a small community, so fewer guides and fixes.
Free, open-source Grammarly alternative for Chrome & Safari — AI grammar checker and text rewriter for any website, powered by your own free Google Gemini API key. No account, no tracking, no subscrip
- Needs:
- works on Mac (per README)
- Trade-off
- Better than Grammarly: a permissive Apache-2.0 license. Worse: a small community, so fewer guides and fixes.
Comparison
✓ yes · ✗ no · – not stated in the README. Hardware details are read from each README and may be incomplete.
Grammarly vs open source: what you give up
- Setup. Grammarly is ready as soon as you sign up. These projects need installing, usually with Python, Node or Docker.
- Hardware. Most READMEs don't state hardware needs; heavier models run much faster with a GPU. 8 mention Mac support.
- Polish and support. Paid products usually have a smoother interface, managed updates and customer support. Open source gives you privacy, no usage limits and no monthly bill.
- Maintenance. 12 of 20 were updated in the last 30 days.
- License. 16 of 20 use a standard open-source license (MIT, Apache, GPL and similar). Check the license before commercial use.
How we picked
Projects that describe themselves as a Grammarly alternative come first, then projects that do the same job, ranked by how well they match and by GitHub stars. Projects that need a paid API key, and projects from Grammarly's own company, are left out. Stars and activity are verified with the GitHub API every night; hardware details come from each README. Full method.
FAQ
Is there a free alternative to Grammarly?
Yes. We list 20 free, open-source GitHub projects that do the same job as Grammarly. The most popular are open-notebook, im-not-ai and obsidian-textgenerator-plugin.
What is the best open-source Grammarly alternative?
It depends on your setup. Most popular: open-notebook. Mac users: PaperForge. Best match for the job: GemType. Compare GitHub stars, license and hardware needs in the table on this page.
Can I run a Grammarly alternative on a Mac?
Yes. According to their READMEs, GemType, Textus and PaperForge run on macOS.
Do I need a GPU to replace Grammarly?
Most READMEs don't state hardware needs. Expect heavier models to run much faster with a GPU.
Are these Grammarly alternatives really free?
Yes. All 20 are open source on GitHub, and projects that need a paid API key are left out. 16 use a standard open-source license such as MIT, Apache or GPL; check the license before commercial use.