OpenAI launched GPT-4, its first flagship successor to the model behind ChatGPT. It was multimodal from the start — accepting image inputs alongside text — and dramatically stronger at reasoning, instruction-following, and exams, scoring in the top 10% on a simulated bar exam.

GPT-4 debuted for ChatGPT Plus subscribers and as a waitlisted API, with 8K and later 32K context variants. Microsoft confirmed its new Bing chat was already running on GPT-4, making it the quiet engine of the search industry's AI pivot.

The release also marked a shift in OpenAI's openness: the company published a system card and red-teaming results but disclosed almost nothing about architecture, training data, or model size — a stance that drew criticism from researchers.