Duden-Mentor vs LanguageTool

Duden-Mentor checks German text for spelling, grammar, punctuation, and style, then suggests corrections. It can flag filler words, repeated wording, and overly long sentences, with suggestions for readability. The service supports German variants for Germany, Austria, and Switzerland, but checks German only. Browser extensions are available for Chrome, Firefox, and Microsoft Edge, and the plug-in works in text fields on services including Gmail, Web.de, GMX.de, Trello, Facebook, and WordPress. A Microsoft Word add-in supports macOS from Word 2016 and Windows from Word 2019. An internet connection is required. Duden says text is encrypted in transit, not used for AI training, and deleted after checking. Basis is free and lists a 10-word personal dictionary and 500 characters without an account. Pur costs €2.99 a month, billed 35,88 € pro Jahr, with 10 test corrections or rewrites monthly. Premium costs €7.95 a month, billed 95,40 € pro Jahr, with 250 monthly text optimizations; Premium Plus costs €9.95 a month, billed 119,40 € pro Jahr, with unlimited optimizations. Paid plans are annually payable and annually cancellable.

LanguageTool is a writing assistant that checks grammar, spelling, punctuation, casing, and style across 31 languages. It also offers tone detection, writing statistics, and paraphrasing modes for making sentences more formal, fluent, simple, or concise. The service works through browser extensions and Windows, macOS, and iOS apps, and integrates with Google Docs, Microsoft Word, Apple Pages, and LibreOffice. Email add-ons are available for Gmail, Outlook, Apple Mail, and Thunderbird. The free version covers spelling, simple punctuation, and some style issues, with a 2,000-character limit per text field; Premium allows up to 150,000 characters. Individual Premium can be billed monthly, quarterly, annually, or every two years, but no plan prices are listed. Text written through the browser add-on is usually not saved; text in the editor is stored and accessible across devices. Teams can manage invited users and share style guides and dictionaries. Business solutions are described as GDPR-conform and support consistent brand voice. Premium has a 14-day money-back guarantee with cancellation and refund without questions.