# LanguageTool Integration for Obsidian

> This community Obsidian plugin checks notes with LanguageTool as you type or on demand, underlines mistakes and offers up to three fixes per issue. Languages are whatever LanguageTool supports (25+). It is only a client: by default it sends text to LanguageTool's cloud; to keep notes private you point it at your own LanguageTool server, for example the erikvl87/languagetool Docker image. AGPL-3.0. Works only inside Obsidian (desktop and mobile); no AI rewriting or plagiarism check.

- Repository: https://github.com/Clemens-E/obsidian-languagetool-plugin
- Official docs: https://github.com/Clemens-E/obsidian-languagetool-plugin#readme
- Checked: 2026-10-15

## What it replaces
- Grammarly: Grammar and spelling checks (partial). Grammar and spelling inside Obsidian notes via LanguageTool; private only with a self-hosted server.

## Facts, with sources

| Question | Status | Answer | Source | Checked |
|---|---|---|---|---|
| Runs on my machine? | Partial | Plugin runs in Obsidian; checks go to LanguageTool's cloud unless you set a self-hosted server URL | https://github.com/Clemens-E/obsidian-languagetool-plugin#privacy-and-self-hosting | 2026-10-15 |
| Code licence | Partial | AGPL-3.0 (strong copyleft) | https://github.com/Clemens-E/obsidian-languagetool-plugin/blob/master/LICENSE.md | 2026-10-15 |
| Model weights licence | Confirmed | No separate model weights | https://github.com/Clemens-E/obsidian-languagetool-plugin#readme | 2026-10-15 |
| Commercial use | Partial | Yes, AGPL-3.0 conditions apply if you modify and distribute or host it | https://github.com/Clemens-E/obsidian-languagetool-plugin/blob/master/LICENSE.md | 2026-10-15 |
| Paid services needed? | Partial | None required (free public API or self-hosted server); LanguageTool Premium API is optional | https://github.com/Clemens-E/obsidian-languagetool-plugin#readme | 2026-10-15 |
| Hardware | Unknown | Not documented; a self-hosted LanguageTool server has its own needs | none found | - |
| Operating systems | Confirmed | Wherever Obsidian runs, desktop and mobile | https://github.com/Clemens-E/obsidian-languagetool-plugin#the-ribbon-icon | 2026-10-15 |
| Setup effort | Confirmed | Easy from Obsidian's Community plugins; medium if you also self-host LanguageTool with Docker | https://github.com/Clemens-E/obsidian-languagetool-plugin#installation | 2026-10-15 |

GitHub: 576 stars, 48 forks, last push 2026-09-05, archived: no.
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Source: RepoQuarry (https://repoquarry.dev/projects/obsidian-languagetool). Data licence: CC BY 4.0. Quotes are from project documentation and belong to their authors.