LinguaCheck – Spelling & Grammar by Cynaps audio visual systems

LinguaCheck checks your German and English texts right where you write them: in e-mails, forms, comments, ticket systems and rich-text editors. All checks run locally in your browser – no account, no server, no AI.

What LinguaCheck checks

• Spelling with Hunspell dictionaries for Germany, Austria, Switzerland, the US and the UK – including German compound words
• Grammar and confused words: their/there, its/it's, your/you're, a/an, das/dass, seit/seid and about 350 more rules
• Punctuation and typography: commas, spaces, quotation marks, dashes
• Style: filler words, wordy phrases, passive voice, redundancy, long sentences, clichés
• Tone, readability, a text score (0–100) and detailed statistics in the editor

How it works

• Mistakes are underlined in the text field; click one to see suggestions
• “Fix all” applies all suggestions at once
• Checks running text: multi-line text fields and editors. Single-line fields (subject, search, postcode …) can be switched on in the settings
• A dedicated editor with notes in the margin; send the revised text back into the form with one click
• Synonyms on double-click
• Interface in German or English; the text language is detected automatically, even in mixed texts
• Personal dictionary, per-site switch, strict “picky” mode and writing goals

Optional AI assistant

If you like, add your own API key (Anthropic Claude or any OpenAI-compatible service). An AI can then check the text right in the field, rewrite it or explain mistakes – on demand. Text is only sent when you explicitly trigger an AI feature and have agreed to the data transmission.

Privacy

Without AI, no text ever leaves your computer. There is no telemetry and no account.

Free

LinguaCheck is free and ad-free. If it helps you, a donation via the button on this page is very welcome.