OpenAI o4-mini is a generative pre-trained transformer model created by OpenAI. On April 16, 2025, the o4-mini model was released to all ChatGPT users (including free-tier users) as well as via the Chat Completions API and Responses API.
Additionally, OpenAI introduced the o4-mini-high model, which was made available exclusively to paid-tier ChatGPT users. The high model was a slower model which had a higher reasoning effort to produce more accurate responses.
Unlike earlier models, o4-mini is capable of processing both text and images. It also allows to perform tasks like analyzing whiteboard sketches during its "chain-of-thought" phase.