Is it allowed to build a GPT client and sell it?

Hi, I’m planning to build a desktop client (Windows) for ChatGPT and i’m gonna use my own API key, then sell it to a bunch of users.

Is it allowed?

I don’t see any prohibitions in Usage policies , but I’m kinda not sure about it.

See also Brand Guidelines. But using your API keys means you’re on the hook for all usage, so also be sure to understand Moderation guidelines. That’s why most GPT clients require you bring your own API key, if the App API Key gets banned then the app is done for.