LanguageTool Alternative for Mac: Native, Local AI, No Subscription

LanguageTool has long been the go-to grammar checker for anyone writing in more than one language. But in February 2026, its browser extension moved real-time checking behind a Premium paywall, and many longtime users started searching for a LanguageTool alternative — ideally one that isn't tied to a browser, doesn't need a subscription, and doesn't send every sentence to a cloud server. If you write on a Mac, there's a genuinely different way to solve this problem. Here's a fair look at what LanguageTool does well, where it falls short on macOS, and what a Mac-native, local-AI alternative looks like in practice.

What Is LanguageTool (and What It Does Well)?

LanguageTool is a grammar, spelling, and style checker that started as an open-source project in Germany and grew into a polished commercial product. It supports more than 30 languages and dialects, and its rule-based engine is genuinely excellent — especially for German. Case and gender agreement, comma placement, false friends for English speakers writing German: these are exactly the kinds of errors LanguageTool's hand-crafted rules catch reliably. For French, Spanish, Dutch, and other European languages, its coverage is similarly strong.

Credit where it's due: if you want a checker with transparent, explainable rules and a free web editor, LanguageTool remains a good product. This article isn't about calling it bad — it's about whether its workflow and pricing model still fit how you write on a Mac.

Why Mac Users Are Looking for a LanguageTool Alternative

Four things push people to look for a LanguageTool alternative, and they've all become more acute recently:

• The subscription keeps growing in scope. Premium runs from roughly $5 per month on a two-year commitment to about $20–25 for month-to-month billing. And since early 2026, real-time underlining in the browser extension — the feature most people actually used — requires Premium after a 14-day trial. The free tier still exists, but it's now largely limited to the web editor with a 2,000-character cap per check.
• It's built around the browser, not the Mac. LanguageTool's center of gravity is its extension and web editor. There is a native Mac app that works in Mail, Notes, and a handful of other programs, but coverage is app-by-app. If you write in Slack, a code editor, a notes app it doesn't support, or any niche tool, you're back to copy-pasting into the web editor.
• Your text is processed in the cloud. Every check sends your writing to LanguageTool's servers. The company has a reasonable privacy policy, and you can self-host the open-source server if you're technical — but the self-hosted version lacks the premium rules, and most people never set it up. For confidential email, client work, or anything under NDA, cloud processing is a real concern.
• Rules flag problems; they don't rewrite. Rule-based checking is precise but shallow. It can tell you a comma is missing; it can't restructure a clumsy sentence, tighten a rambling paragraph, or shift your tone from casual to formal. LanguageTool has added AI paraphrasing, but it's metered on the free plan and lives inside its own editor.

We've written a detailed head-to-head in our WunderType vs LanguageTool comparison — this article focuses on the bigger question of what you should switch to.

The Mac-Native Alternative: WunderType

WunderType approaches the problem from the opposite direction. Instead of adding a checker to specific apps, it uses the macOS Accessibility API to work in every app. Select any text — in Mail, Notes, Slack, Chrome, VS Code, anywhere — press a keyboard shortcut, and the corrected or improved text replaces your selection in place. No extension, no web editor, no copy-paste round trip.

It ships with five built-in modes, each on its own shortcut:

• Correct Grammar — fix spelling, grammar, and punctuation without changing your meaning
• Improve Writing — rewrite for clarity and flow
• Make Concise — cut filler and tighten sentences
• Make Formal — polish for professional contexts
• Make Casual — relax the tone

Beyond the built-ins, you can create unlimited custom prompts, each with its own shortcut. A prompt like “Fix the German grammar in this text” or “Translate this to German” becomes a single keystroke that works system-wide. That flexibility is what makes an AI-based approach fundamentally broader than a rule engine — if you can describe the transformation, you can bind it to a shortcut. For a deeper look at how AI correction compares to traditional checkers, see our guide to using an AI proofreader.

The other structural difference is where the intelligence runs. WunderType lets you choose between four AI providers:

• On-Device AI — local models running directly on Apple Silicon via Apple's MLX framework, no internet required
• Ollama — free local models like Llama or Qwen running on your Mac
• OpenAI — your own API key, stored in the macOS Keychain, sent directly to OpenAI with no middleman
• OpenRouter — one key for hundreds of models from different labs

With the two local options, your text never leaves your Mac — not to LanguageTool's servers, not to anyone's. WunderType itself has no backend, no accounts, no analytics, and no telemetry, and it's a one-time purchase on the Mac App Store rather than a subscription.

LanguageTool vs WunderType at a Glance

	LanguageTool	WunderType
Approach	Rule-based checking with underlines and suggestions	AI correction and rewriting applied in place
Languages	30+ languages with hand-crafted rules	Any language your chosen AI model supports
Where it works	Browser extension, web editor, supported apps	Every Mac app, system-wide
AI or rules	Rules first, metered AI paraphrasing on top	AI throughout — correction, rewriting, tone, custom prompts
Pricing	Free tier (limited); Premium ~$5–25/month	One-time purchase, no subscription
Privacy	Text processed on LanguageTool's servers	Fully local possible (MLX/Ollama); no telemetry, no accounts
Platform	Web, Windows, macOS, iOS, browser extensions	Native macOS app (macOS 15+, under 5 MB of memory)

Checking German (and Other Languages) with AI

German deserves its own section, because it's where LanguageTool has historically been strongest — and where the AI approach has quietly caught up. Modern language models handle German case endings, adjective declension, verb position in subordinate clauses, and formal/informal register (du vs. Sie) remarkably well. The difference is that an AI model doesn't just flag the error; it rewrites the sentence correctly, and it can do so at whatever level of intervention you ask for — from a light grammar pass to a full stylistic polish.

Because WunderType simply sends your selection to the model you chose, it corrects and improves text in any language that model supports — German, French, Spanish, Dutch, Polish, and dozens more, with no per-language rule sets to maintain. Bilingual writers get a particular benefit: you can keep one shortcut for English and a custom prompt for German, and both work in the same apps with the same workflow. We've covered the German use case in depth in our German grammar checker guide, and if you regularly move between the two languages, our guide to English to German translation with correct grammar shows how a custom translation prompt works in practice.

A fair caveat: for learners who want to understand why something is wrong, LanguageTool's rule explanations are more pedagogical. AI correction gives you the fixed text; rules give you the grammar lesson. Some people genuinely want both.

Is LanguageTool Premium Still Worth It?

It depends on where you write. If you live in Google Docs in the browser, write mostly in one of LanguageTool's well-supported languages, and value explainable rule-based suggestions, Premium at the annual or two-year rate (roughly $5–7/month) is reasonable value. The calculation gets worse if you write across many Mac apps — you're paying a recurring fee for a checker that only sees a slice of your writing. Over three years, Premium costs somewhere between $180 and $500 depending on your billing cycle; a one-time purchase plus free local AI costs what it costs on day one and nothing after.

Is There a Free LanguageTool Alternative?

If your priority is simply “free,” you have options, each with trade-offs. LanguageTool's own open-source server can be self-hosted for unlimited basic checking, but setup is technical and the premium rules aren't included. Harper is a fast, open-source, on-device checker, but it's English-only. Apple's built-in spell check is free and system-wide but catches only surface errors. None of these give you multilingual AI rewriting. WunderType isn't free — it's a one-time purchase — but paired with free local models via Ollama or MLX it has zero ongoing costs, which over any subscription's lifetime makes it the cheaper path. If you're weighing it against other paid tools, our Grammarly alternative for Mac breakdown covers how the one-time-purchase math works out.

Verdict: Which Should You Choose?

Stick with LanguageTool if: you write primarily in the browser or in its supported apps, you want transparent rule-based explanations (especially as a language learner), and the annual Premium price fits your budget. It remains one of the best rule-based checkers ever built, particularly for German.

Choose WunderType if: you write across many Mac apps and want one shortcut that works everywhere, you're done with subscriptions, you want AI that rewrites rather than just underlines, or you handle text that should never touch a cloud server. It's the LanguageTool alternative built the way a Mac tool should be: native, fast, private, and paid for once.

Download WunderType from the Mac App Store