LanguageTool

Grammar, spelling and style checker for 30+ languages, with AI rephrasing

Freemium languagetool.org

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Pricing

Freemium

API

Yes

Open source

Yes

Platforms

WebChromeWindowsmacOSiOSAPI

What is LanguageTool?

LanguageTool is a grammar and style checker that flags spelling, grammar, punctuation, casing and style issues as you type. It also includes an AI paraphrasing tool that can rewrite sentences to sound more formal, fluent, simple or concise.

It supports more than 30 languages and dialects. The main ones are English (six regional variants), Spanish, German, French, Dutch and Portuguese. LanguageTool runs as browser add-ons for Chrome, Edge, Firefox, Opera and Safari, as plugins for Google Docs, Microsoft Word, Apple Pages and LibreOffice, inside email clients such as Gmail and Thunderbird, and as desktop apps for Windows and macOS. There is also an iOS app.

The free Basic plan suits occasional writers. Premium adds longer texts, extra checks and unlimited rephrasing for professionals. Teams and Business plans add shared dictionaries, style guides and GDPR-compliant options for organizations. Developers can use the Proofreading API.

Key features

Grammar, spelling, punctuation and style checking
AI sentence paraphrasing in several tones
Support for 30+ languages and dialects
Browser add-ons for Chrome, Edge, Firefox, Opera, Safari
Plugins for Google Docs, Word, Pages, LibreOffice
Personal dictionary and Picky Mode
Team style guides and shared dictionaries
Proofreading API with daily call-limit plans

Use cases

Who it's for

StudentsProfessional writersMultilingual usersBusiness teamsDevelopers

Multilingual writing

Check texts in German, French, Spanish, Dutch, Portuguese and other languages with a single tool.

Proofreading emails

Catch errors in Gmail, Apple Mail, Thunderbird or Outlook (beta) before you send.

Consistent team writing

Teams share a style guide and dictionary so company terms are used the same way everywhere.

Adding checks to apps

Developers can use the Proofreading API to add grammar checking to their own software.

LanguageTool pricing

From the vendor's site, checked Oct 26, 2026; we re-check prices monthly. Prices change — confirm on their pricing page.

Basic

Free

Up to 2,000 characters per text field
3 AI sentence rephrasings per day
Limited Picky Mode

Premium

monthly, quarterly, annual or 2 years

Price not shown on page

Up to 150,000 characters per text field
20,000+ additional checks
Unlimited AI paraphrasing
Style Guide, Personal Dictionary, Text Statistics
14-day money-back guarantee

Teams

per user

Price not shown on page

All Premium features
User management by email
Team style guide and dictionary
2 to 1,000 users

Business

Custom

GDPR-compliant solutions for organizations

How LanguageTool compares

LanguageTool has a free plan, like 3 of the 4 alternatives below.
It offers an API, which only 1 of the others does.
It is open source, the only one here.

Tool	Starts at	Free plan	Free trial	API	Open source
LLanguageTool	—		—
HHemingway Editor	$8.33/mo	—		—	—	LanguageTool vs Hemingway Editor
PProWritingAid	—		—	—	—	LanguageTool vs ProWritingAid
GGrammarly	—			—	—	LanguageTool vs Grammarly
GGinger	—		—		—	LanguageTool vs Ginger

Compare 8 capabilities

Capability	LanguageTool	Hemingway Editor	ProWritingAid	Grammarly	Ginger
AI rewrites	—
Tone adjustment				—	—
Plagiarism checker	—	—			—
AI text detection	—	—	—		—
Non-English checking		—	—		—
Word/Google Docs add-in		—
Browser extension		—	—
Custom style guide		—

Capabilities as stated on each vendor's own site; — means the site doesn't say. The closest alternatives in our directory by category. “Starts at” is the cheapest paid plan per month, as each vendor lists it.

LanguageTool data and privacy

Trains AI on your content

“Learneo does not use inputs from any LanguageTool user (Individual or Team Plan) to train its language algorithms or models. This is a default setting in LanguageTool that does not require an opt-out or any action by the user.”

Data retention

Not stated

Where data is stored

Not stated

Security and compliance

GDPR

From LanguageTool's own privacy and security pages , checked Oct 28, 2026. We only show what the vendor states in writing; “not stated” means the pages don't say.

Who's behind LanguageTool

Company: Learneo, Inc.
Based in: San Francisco, United States
Founded: 2003

From LanguageTool's own about, terms and privacy pages, checked Oct 28, 2026.

Pros and cons

Strengths

Free Basic plan is available
Supports 30+ languages and dialects
Many integrations, including browsers, office suites and email clients
Source code is published on GitHub

Limitations

Free plan is limited to 2,000 characters per text field
Free plan allows only 3 AI rephrasings per day
Prices did not display on the pricing pages
Outlook add-on is still in beta

LanguageTool FAQ

Is LanguageTool free?

Yes. The Basic plan is free, with a limit of 2,000 characters per text field and 3 AI rephrasings per day. Premium removes these limits.

Which billing periods does Premium offer?

Monthly, quarterly, annual or 2-year billing. Subscriptions renew automatically and can be canceled at any time. There is a 14-day money-back guarantee.

Where can I use it?

In browser add-ons, in Google Docs, Word, Pages and LibreOffice, in email clients, in desktop apps for Windows and macOS, and in an iOS app.

Is there an API?

Yes. The Proofreading API has monthly plans ranging from 100 to 10,000 calls per day.

How do I pay?

PayPal and credit card are accepted.