I actually wrote MinimalGPT as a project for myself because I found using ChatGPT annoying for certain things.

It’s just a minimal chat client where you provide an OpenAI API key for GPT and you’re off to the races.

Conversations and all data (besides the messages you send to OpenAI) are stored locally to your browser.

https://minimalgpt.app, it’s also a PWA application so you can save it to your mobile Home Screen for a full app experience.

GitHub Repo with a fleshed out readme for more info.

Not official versions supposedly.