LanguageTool is a genuinely good tool. But its free tier caps each check at around 10,000 characters, keeps some suggestions behind a subscription, and sends your text to its servers. Korr has no cap, no premium tier and no server at all: everything runs on your device.
100% free. No account. No character limit. No subscription.
LanguageTool's free tier checks roughly 10,000 characters at a time, so long documents have to be split. Korr has no limit of any kind, because there is no server paying for your check.
Part of LanguageTool's value sits behind a subscription. Korr has no paid tier at all: what you see is the whole product, for everyone.
LanguageTool can run offline, but you have to self-host its Java server. Korr is offline by default, with nothing to install on a server and nothing to maintain.
LanguageTool works through a browser add-on. Korr adds a system-wide shortcut, so you also fix text in programs a browser extension never reaches.
| Korr | LanguageTool (free) | LanguageTool (self-hosted) | |
|---|---|---|---|
| Price | Free | Free tier + paid | Free |
| Character limit | None | 10,000 per check | None |
| Setup required | None open a page | None | Run a Java server |
| Works offline | Yes, by default | No | Yes |
| Text stays on your device | Always | No | Yes |
| Review each change | One by one | One by one | One by one |
| Personal dictionary | Yes, on your device | In your account | In your account |
| Account | Never | For premium | Not required |
| Paid tier holding features back | No | Yes | Premium rules excluded |
| System-wide shortcut (desktop) | Yes (Ctrl+Alt+C) | Browser + add-ons | Browser + add-ons |
| Languages | 5 FR, EN, ES, IT, PT | 30+ | 30+ |
Comparison as of September 2026. LanguageTool can be self-hosted, but that means installing and maintaining a server; its premium suggestions and n-gram data are not included.
We ran Korr over nine corpora of forty sentences, in three languages, half of them already correct. Here is what came out, and the method is published with it.
98.67 % precision · 96.91 % F1
98.23 % precision · 96.82 % F1
100 % precision · 96.76 % F1
0 out of 174
See the full method and the misses
Korr does not silently rewrite your text. Every change is listed, shown inside its sentence and labelled, and you reject the ones you disagree with, one at a time.
Your proper nouns, brand names and trade words, added in one click: Korr stops correcting them. The list stays on your device, with no account and no sync.
Korr is not better at everything, and pretending otherwise would not help you choose. Stay with LanguageTool if:
LanguageTool covers 30+ languages. Korr covers four: French, English, Spanish and Italian. If you write in German, Dutch or Polish, LanguageTool is the right tool.
LanguageTool Premium offers paraphrasing and style suggestions that Korr does not try to replicate. Korr focuses on correctness.
A self-hosted LanguageTool server is also free, offline and private. If you have already set one up, you have solved the same problem a different way.
No. Korr has no character limit, no daily quota and no monthly quota. The correction runs on your own machine, so there is no server cost to ration.
Korr is free with no tiers at all. There is no premium plan, so no feature is held back and no suggestion is hidden behind a subscription.
No. LanguageTool's offline mode means running its Java server yourself. Korr runs inside the page or the Windows app, so offline works out of the box with nothing to maintain.
No. LanguageTool covers 30+ languages; Korr covers French, English, Spanish and Italian. Korr's aim is depth on those, not breadth.
No, you can test it. Load the page once, then cut your connection: the correction keeps working, because nothing ever needed to leave your device.
Yes, on the Chrome Web Store. It corrects text directly in Gmail, Slack or any text field, without copying and pasting, and it runs the same local engines: nothing is sent anywhere. It also installs in Edge, which accepts extensions from the Chrome Web Store.