One of the more terribly named models, o4-mini drops the “GPT” element of the naming scheme and awkwardly swaps the 4o around to o4. It’s a smaller model, which means it’s not stuffed to the brim with as much random internet information as a full-sized model.

ChatGPT isn't based on one AI model, but many. As it turns out, OpenAI has a support document listing the times it thinks you should be using each model.

OpenAI has quietly released an updated overview of the capabilities and usage limits of its ChatGPT Enterprise models, offering businesses clear guidance