In short
Zack KI corrects selected text with Alt+4 and improves it with Alt+3, directly in your app. Alt+1 lets you ask questions about it. Grammarly offers suggestions as you type; DeepL Write focuses on style and wording.
How the tools work
| Grammarly | DeepL for Windows | Zack KI | |
|---|---|---|---|
| Working style | Suggestions in the text field while you type | Ctrl+C+C translates; DeepL Write polishes style and tone | Shortcut on selected text; chat for everything else |
| Corrects in place | Accept a suggestion in the field | Ctrl+Shift+C+C replaces your text with the translation | Alt+4 corrects, Alt+3 improves and replaces the selection |
| Questions about the text | Prompts for rewriting | Not documented | Explain, summarise, ask follow-up questions |
| Files and screenshots | Not documented | Document translation | PDF, Office files, images and screen captures |
| German | Supported | Supported | German and English interface; answers in your language |
Provider sources, 17 October 2026: Grammarly for Windows, DeepL for Windows, LanguageTool for Windows. We develop Zack KI.
Save your writing instructions
Save a target language or your company’s style as a custom action, so you do not have to repeat the instruction.
Related questions
Does Alt+4 change my wording?
Alt+4 is for spelling, grammar and punctuation. Alt+3 also rewrites the text.
Can I undo a replacement?
Many programs restore the previous text with Ctrl+Z. The target program decides how far you can undo.