If you are evaluating this tool, here is what matters: LanguageTool is one of the few grammar checkers built from the ground up to work across many languages rather than optimizing for English alone, and it is open source with an API you can call or a server you can run yourself. That combination shapes almost everything about who it fits and where it falls short. Before deciding, it helps to separate what you actually get from the marketing framing.
What you actually get
At its core, LanguageTool checks grammar, spelling, punctuation, casing, and style. It supports more than 30 languages and dialects, with the deepest coverage in English, German, Portuguese, Spanish, French, and Dutch. English alone is split into six regional varieties (US, UK, Canadian, Australian, New Zealand, and South African), which matters more than it sounds: a checker that flags "colour" as a typo in British text is worse than useless, and choosing the correct variety avoids that noise. The engine is described by the vendor as AI-based, and it combines that with rule-based linguistic analysis, which is a practical strength. Rule-based systems are transparent and predictable for things like agreement and punctuation, while the AI layer handles the fuzzier judgment calls around phrasing and style.
The style suggestions go beyond correctness. LanguageTool flags overused phrases, redundant wording, and awkward word choice, and it includes an AI paraphrasing feature that rewrites a sentence to be simpler, more formal, or more concise. That last capability is the one most people will lean on when they want to tighten prose rather than just fix errors, though it is gated on the paid tier for unlimited use.
Where LanguageTool is quietly ahead of many competitors is distribution. It runs as a browser add-on for Chrome, Firefox, Edge, Safari, and Opera; as desktop apps for macOS and Windows; inside email clients including Gmail, Apple Mail, Outlook, and Thunderbird; and within office tools such as Google Docs, Microsoft Word, Apple Pages, and LibreOffice. For developers, there is a public HTTP proofreading API, and because the project is open source you can embed it in a Java application or stand up your own HTTP server. If you have a data-sensitivity requirement, that self-hosting path is a real differentiator, not a checkbox.
Where it earns its place
The multilingual coverage is the headline reason to pick this tool. If you write in German and English, or edit Spanish and Portuguese documents in the same week, most single-language assistants force you into workarounds or a second subscription. LanguageTool handles the switch natively. For non-native English writers in particular, this is the difference between a tool that understands your first language too and one that only speaks the language you are struggling with.
The open-source foundation and the ability to run the engine locally are the second reason, and they appeal to a narrower but important audience. Teams handling confidential or regulated text, or developers who want proofreading inside their own product without shipping user content to a third party, can self-host. The vendor also states that the browser add-on stores no text, which is a meaningful privacy posture for people who are wary of everything they type being logged. The public API means proofreading can be wired into internal editors, CMS workflows, or support tooling.
The free tier is the third point in its favor, because it is usable rather than a demo. It covers spelling, basic punctuation, and some style issues, with a 2,000-character-per-text-field limit. For emails, short posts, and paragraph-length editing, many people never hit a wall. You can find other options in the same space on our AI grammar checker category page if you want to compare the free experiences side by side.
The tradeoffs and limits
The free version is deliberately partial. LanguageTool reserves its full checking depth, more than 20,000 additional checks by the vendor's count, unlimited AI paraphrasing, the custom Style Guide, the Personal Dictionary, Text Statistics, and full "Picky Mode" for Premium. In practice that means the free tier catches the obvious mistakes but withholds the polish, and the 2,000-character cap forces long documents to be checked in chunks. If you are editing anything book-length or working professionally, you will feel the ceiling quickly.
Depth of suggestion also varies by language. The tool supports 30-plus languages, but the vendor names only a handful as primary, and it is reasonable to expect the rule sets and AI behavior to be richer for English and German than for a less-resourced language. Treat the smaller-language support as competent spell and grammar checking rather than nuanced style coaching until you have tested it on your own text.
Finally, the AI paraphraser and style engine are assistants, not authorities. They will occasionally suggest a rewrite that changes your meaning or flattens a deliberate voice, so the sentence-level suggestions need a human editor's eye, especially in formal or creative writing. That is true of every tool in this class, but it is worth stating plainly rather than assuming the output is always an improvement.
The pricing reality
LanguageTool follows a freemium model. The free plan is genuinely free with no listed catch beyond the 2,000-character limit and the reserved Premium features. Premium raises the per-field limit to 150,000 characters, unlocks the full checking engine and unlimited paraphrasing, and adds the Style Guide, Personal Dictionary, Text Statistics, and browser add-on access to the paid experience. There is also a Teams plan for small teams of up to 20 members, with user management, shared style guides, and team dictionaries, priced to scale with the number of seats.
One honest caveat: the vendor does not reliably publish the exact Premium prices on its own pricing page. When checked, the page offered monthly, quarterly, annual (marked as the bestseller), and two-year billing intervals with VAT included, but did not display the actual figures, and referenced a limited-time discount without a number attached. Because of that, this review does not state a specific dollar or euro amount; confirm the current price directly on the checkout page for your region before committing, since pricing can vary by currency and promotion.
How it compares
The most useful way to frame alternatives is by what you would be trading away. If you only ever write in English and want the deepest possible style and tone coaching in that one language, a dedicated English-first assistant may feel more polished, and you would be giving up multilingual coverage and self-hosting to get it. If your priority is embedding proofreading in your own software or keeping text on your own infrastructure, the open-source, self-hostable nature of LanguageTool is hard to match, and most closed commercial tools cannot offer it at all. Rather than name competitors that are not verified here, the practical test is simple: run the same multilingual document through two or three tools from our tools directory and judge the suggestions on your actual writing.
Final verdict
LanguageTool is a strong, credible choice for multilingual writers, students, academics, non-native English speakers, and developers who need proofreading they can host or call programmatically. Its open-source core and privacy posture set it apart from most closed alternatives, and the free tier is good enough for everyday short-form writing. The reasons to look elsewhere are narrow: if you write only in English and want maximum stylistic hand-holding, or if you need certainty on price before signing up and are not willing to check the regional checkout page. For everyone whose work crosses languages or who cares where their text is processed, it is worth a serious trial. You can read more comparisons on our blog.
Common questions about LanguageTool
How many languages does LanguageTool support?
It supports more than 30 languages and dialects. The deepest coverage is for English, German, Portuguese, Spanish, French, and Dutch, and English is available in six regional varieties including US, UK, Canadian, Australian, New Zealand, and South African.
Is there a free version, and what are its limits?
Yes. The free plan checks spelling, basic punctuation, and some style issues, with a limit of 2,000 characters per text field. Premium raises that limit to 150,000 characters and unlocks the full checking engine and unlimited AI paraphrasing.
Can I run LanguageTool on my own servers?
Yes. LanguageTool is open source, and the developer documentation describes running it locally through an embedded HTTP server or embedding it in Java applications, in addition to a public HTTP proofreading API. The browser add-on is also stated to store no text.
What does the Premium plan add over the free tier?
Premium adds more than 20,000 additional checks, unlimited AI sentence paraphrasing, a custom Style Guide, a Personal Dictionary, Text Statistics, full Picky Mode, and the higher 150,000-character limit per text field.
Is there a plan for teams?
Yes. A Teams plan supports small teams of up to 20 members and includes user management, shared style guides, and team dictionaries, with pricing that scales by the number of users.
