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languagetool-org
languagetool
Java2014–2026
languagetool-org / languagetool

languagetool

Style and Grammar Checker for 25+ Languages

25Distinct people
28Mentions
1Explicit recommenders
15.3KGitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

Style and Grammar Checker for 25+ Languages

GitHub

Where it is used

No documented product use was verified in the last source check.

What people are saying

I have been using LanguageTool[1] for years as "an open source alternative to [old school] Grammarly". It doesn't do that fancy "make this text more professional" AI stuff like…

slg used a recommendation phrase. One indexed comment matches. This is a phrase match, not a verdict.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 5:04:57 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year28 dated mentions

Observed mentions: 2014-02-02 02:26:53 UTC to 2026-09-23 17:45:25 UTC.

02468102014-01-01 00:00:00 UTC to 2015-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments20142015-01-01 00:00:00 UTC to 2016-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2016-01-01 00:00:00 UTC to 2017-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2017-01-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2018-01-01 00:00:00 UTC to 2019-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments20202021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 5 mentions; 1 submissions, 4 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 10 mentions; 0 submissions, 10 comments2023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 3 mentions; 0 submissions, 3 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments2026-01-01 00:00:00 UTC to 2027-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments. Incomplete calendar period.2026*

* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20142014-01-01 00:00:00 UTC2015-01-01 00:00:00 UTC202
20152015-01-01 00:00:00 UTC2016-01-01 00:00:00 UTC000
20162016-01-01 00:00:00 UTC2017-01-01 00:00:00 UTC000
20172017-01-01 00:00:00 UTC2018-01-01 00:00:00 UTC000
20182018-01-01 00:00:00 UTC2019-01-01 00:00:00 UTC000
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC101
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC101
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC514
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC10010
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC303
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC202
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC202
2026 (partial)2026-01-01 00:00:00 UTC2027-01-01 00:00:00 UTC202

From the project README

An excerpt from the repository, fetched Nov 13, 2026.

Read the project’s introduction
LanguageTool LanguageTool is open-source proofreading software for English, Spanish, French, German, Portuguese, Polish, Dutch, and more than 20 other languages. It finds many errors that a simple spell checker cannot detect. LanguageTool Forum How to run your own LanguageTool server HTTP API documentation How to use our public server via HTTP How to use LanguageTool from Java (Javadoc) For more information, please see our homepage, at languagetool.org, this README, and CHANGES. The LanguageTool core (this repo) is freely available under the LGPL 2.1 or later. Docker Try one of the following projects for a community-contributed Docker file: github.com hub.docker.com/r meyayl/docker-languagetool meyay/languagetool Erikvl87/docker-languagetool erikvl87/languagetool silvio/docker-languagetool silviof/docker-languagetool Contributions The development overview describes how you can contribute error detection rules. For more technical details, see our dev pages. Scripted installation and building To install or build using a script, simply type: #!/usr/bin/env sh curl -L https://raw.githubusercontent.com/languagetool-org/languagetool/master/install.sh | sudo bash $options If you wish to have more options, download the install.sh script. Usage options follow: sudo bash install.sh <options> Usage: install.sh <option> <package> Options: -h --help Show help -b --build Builds packages from the bleeding edge development copy of LanguageTool -c --command <command> Specifies post-installation command to run (default gui when screen is detected) -q --quiet Shut up LanguageTool installer! Only tell me important stuff! -t --text <file> Specifies what text to be spellchecked by LanguageTool command line (default spellcheck.txt) -d --depth <value> Specifies the depth to clone when building LanguageTool yourself (default 1). -p --package <package> Specifies package to install when building (default all) -o --override <OS> Override automatic OS detection with <OS> -a --accept Accept the oracle license at http://java.com/license. Only run this if you have seen the license and agree to its terms! -r --remove <all/partial> Removes LanguageTool install. <all> uninstalls the dependencies that were auto-installed. (default partial) Packages(only if -b is specified): standalone Installs standalone package wikipedia Installs Wikipedia package office-extension Installs the LibreOffice/OpenOffice extension package Commands: GUI Runs GUI version of LanguageTool commandline Runs command line version of LanguageTool server Runs server version of LanguageTool Alternate way to build from source Before start: you will need to clone from GitHub and install Java 17 and Apache Maven. Warning: a complete clone requires downloading more than 500 MiB and needs more than 1 500 MiB on disk. This can be reduced, if you only need the last few revisions of the master branch by creating a shallow clone: #!/usr/bin/env sh git clone --depth 5 https://github.com/languagetool-org/languagetool.git A shallow clone downloads less than 60 MiB, and needs less than 200 MiB on disk. In the root project folder, run: #!/usr/bin/env sh mvn clean test (Sometimes, you can skip Maven step for repeated builds.) #!/usr/bin/env sh ./build.sh languagetool-standalone package -DskipTests Test the result in languagetool-standalone/target/. #!/usr/bin/env sh ./build.sh languagetool-wikipedia package -DskipTests Test the result in languagetool-wikipedia/target. Now, you can use the bleeding edge development copy of LanguageTool *.jar files, be aware that it might contain regressions. How to run under Mac M1 or M2 Install Brew for Rosetta: #!/usr/bin/env sh arch -x86_64 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)" Install OpenJDK for Rosetta: #!/usr/bin/env sh arch -x86_64 brew install openjdk Install Maven for Rosetta: #!/usr/bin/env sh arch -x86_64 brew install maven Now, run the build scripts. License Unless otherwise noted, this software – the LanguageTool core – is distributed under the LGPL; see COPYING.txt.
Read the full README on GitHub

What Hacker News says

28 sources
JetBrains’s default grammar checking plugin[1] is actually built on languagetool[2], a pretty decent grammar checker that also happens to be partly open source and self-hostable[3]. Sadly, they have lately shoved in a few (thankfully optional) crappy LLM-based features (that don’t even work well in the first place) and coated their landing page in endless AI keywords, but their core engine is still more traditional and open-source, and hasn’t really seemed to change in years. You can just run it on your own device and point their browser and editor extensions to it. [1] https://plugins.jetbrains.com/plugin/12175-natural-languages... [2] https://languagetool.org -- warning: is coated in somewhat-misleading AI keywords [3] https://github.com/languagetool-org/languagetool
In Grammarly is offering ‘expert’ AI reviews from famous dead and living writers
LanguageTool (a Grammarly competitor) is also open source and can be managed locally: https://github.com/languagetool-org/languagetool I generally run it in a Docker container on my local machine: https://hub.docker.com/r/erikvl87/languagetool I haven't messed with Harper closely but I am aware of its existence. It's nice to have options, though. It would sure be nice if the Harper website made clear that one of the two competitors it compares itself to can also be run locally.
In Harper – an open-source alternative to Grammarly
slg·Sep 18, 2024Recommendation phrase
I have been using LanguageTool[1] for years as "an open source alternative to [old school] Grammarly". It doesn't do that fancy "make this text more professional" AI stuff like this or Grammarly can now do, but they offer a self-hosted version so you don't need to send everything you write to OpenAI. If all you want is a better spelling/grammar checker, I highly recommend it. [1] - https://github.com/languagetool-org/languagetool
In Scramble: Open-Source Alternative to Grammarly
In some ways, I think computational linguistics has missed a mark. We have dictionaries, lexicons, grammar engines, spell checkers, pluralization rules, tries, quotation disambiguation, sentiment analyzers, word segmentation, and more. You'd think we could roll all these into a unified, standard definition format. My KeenWrite editor, for instance, uses: * https://github.com/DaveJarvis/KeenSpell (spell check, lexicon) * https://github.com/DaveJarvis/KeenQuotes (curls straight quotes) * https://github.com/DaveJarvis/KeenWrite/blob/main/R/pluraliz... (pluralization) * https://lucene.apache.org/ (word segmentation) I was looking at integrating LanguageTool[0] for grammar and realized that it has partial functionality for KeenQuotes (lexing and tokenization), duplicates the SymSpell algorithm used by KeenSpell, and because it offers grammar c
Read the rest
orrections it likely can pluralize words, as well. Unifying those for English alone would be a massive undertaking. At present, KeenWrite parses prose in multiple, redundant passes. While this works, I think it'd be great to start with a basic lexer/tokenizer that can emit tokens at blazing speeds[1], which feeds into higher-level abstractions. [0]: https://github.com/languagetool-org/languagetool [1]: https://github.com/DaveJarvis/KeenQuotes/blob/main/src/main/...
In A spellchecker used to be a major feat of software engineering (2008)
No subscription is required for the base version no account, either. Of course, the base version doesn't have all the features as premium, but it is still excellent, in my opinion. I have used the free version for years. There is an offline version, as it is open source. The full text isn't stored on the servers, but you can always just deploy it yourself for maximum privacy: https://dev.languagetool.org/http-server Furthermore, there are options for docker: https://github.com/languagetool-org/languagetool#docker
In Language Tool – Open-source Grammarly alternative
Unlike other products, self hosting only gives you the same as their basic version. So even keeping it up to date will never match their premium offering. This is of course fine, just making people aware before they spend time setting it up because they don't make this very clear (I had to find a Github issue to get this conformation in writing) The free self-hosted version you can download from https://languagetool.org/download/ lacks all the premium rules (several thousand rules for English, German, French, Spanish and Dutch) and AI-based rules.[1] [1]: https://github.com/languagetool-org/languagetool/issues/6750
In Language Tool – Open-source Grammarly alternative
Just before you fall into the same trap I did of setting a self hosted version be aware: The free self-hosted version you can download from https://languagetool.org/download/ lacks all the premium rules (several thousand rules for English, German, French, Spanish and Dutch) and AI-based rules.[1] My suspicion is the basic self-hosted version may no better then what you would already get in something like LibreOffice. [1]: https://github.com/languagetool-org/languagetool/issues/6750
In Ask HN: Do You Trust Grammarly?

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