In short
Zack KI picks up selected text with Alt+1 and inserts answers back into your app. The ChatGPT app opens your ChatGPT account with Alt+Space; on Windows, you copy text into it yourself.
The main differences
| ChatGPT Windows app | Zack KI | |
|---|---|---|
| Shortcut | Alt+Space opens the companion window while the app is running | Alt+1 with selection, Alt+2 empty chat, Alt+Shift+1 last chat |
| Selected text | Work with Apps is documented for macOS only | Taken over automatically from most Windows programs |
| Answer back into the app | Copy and paste | Insert at the cursor or replace the selection |
| Correct text in place | Not documented | Alt+3 improves, Alt+4 corrects and replaces the selection |
| Screenshots | Via the Snipping Tool | Alt+1 with nothing selected |
| Files | Upload in the chat and the companion window | Select files in Explorer and press Alt+1, or drag them in |
| Models | OpenAI models in your ChatGPT plan | Zack Quick and Deep, or your own API key including local models |
| Chat history | Stored in your ChatGPT account | Stored on your PC |
Provider sources, 17 October 2026: OpenAI: Using the ChatGPT Windows app, OpenAI: Windows app release notes, OpenAI: Work with Apps on macOS. We develop Zack KI.
Keep using your ChatGPT account
Choose the ChatGPT app for chats across devices, custom GPTs or image generation.
OpenAI models in Zack KI
You can use OpenAI models in Zack KI with your own API key. OpenAI bills API usage separately; your ChatGPT subscription does not cover it.
Related questions
Is Zack KI an official ChatGPT app?
No. Zack KI is an independent Windows app from Zack Software in Germany. It can use OpenAI models if you add your own API key.
Can I import my ChatGPT history?
No. Zack KI starts with its own local history.