Open-source alternatives to Grammarly
Looking to replace Grammarly with something free and open-source? These 3 tools are the best open alternatives in 2026 — most are self-hostable, so you keep full control of your data and pay no subscription.
At a glance: how they compare
Click a column to sort — the best one depends on what matters to you.
| Alternative | Stars | Language | License | Last commit | In one line |
|---|---|---|---|---|---|
| LanguageTool | ★ 15k | Java | LGPL-2.1 | 8 days ago | Open-source grammar and style checker, self-hostable. |
| Harper | ★ 15k | Rust | Apache-2.0 | 6 days ago | Offline grammar checker by Automattic (WordPress): nothing you type leaves your machine. |
| Vale | ★ 6.1k | Go | MIT | 6 days ago | Style-guide linter for teams: enforce your own writing rules across docs. |
Which one should you pick?
LanguageTool
Open-source grammar and style checker, self-hostable. Its LGPL-2.1 license keeps the project and its forks open-source forever, and commercial use is allowed. Because it is self-hostable, your data can stay entirely on your own infrastructure.
Harper
Offline grammar checker by Automattic (WordPress): nothing you type leaves your machine. Its Apache-2.0 license is permissive — free to use commercially, embed and modify. Because it is self-hostable, your data can stay entirely on your own infrastructure.
Vale
Style-guide linter for teams: enforce your own writing rules across docs. Its MIT license is permissive — free to use commercially, embed and modify. Because it is self-hostable, your data can stay entirely on your own infrastructure.
Switching from Grammarly without the drama
- Export your data from Grammarly first — most tools above can import standard formats.
- Run your top pick in parallel for a week or two before committing; self-hosted options can be tried locally in minutes.
- Migrate one team or one project at a time, keeping the old account read-only until everything checks out.
FAQ
What is the best open-source alternative to Grammarly?
The top open-source alternative is LanguageTool — Open-source grammar and style checker, self-hostable. The full ranked list is above.
Are these Grammarly alternatives free?
Yes. Every tool listed is open-source and free to use; most can be self-hosted so you keep full control of your data.
Can I self-host an alternative to Grammarly?
Most of these tools are designed to run on your own server or machine, giving you privacy and no subscription fees.
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