If you’ve been experimenting with custom GPTs inside ChatGPT, here’s a welcome upgrade: OpenAI now lets users pick from all available models when building or running a custom GPT, not just GPT-4o.

Notably, GPT-5.3-Codex is the first OpenAI model that was used to create itself: The team used early versions of the model to debug its training, manage its deployment, and diagnose test results and ...

The new coding model released Thursday afternoon, entitled GPT-5.3-Codex, builds on OpenAI’s GPT-5.2-Codex model and combines insights from the AI company’s GPT-5.2 model, which excels on non-coding ...

Today Microsoft is incorporating GPT-5, OpenAI’s best AI system to date, into a wide variety of its products, to bring new reasoning capabilities and improvements to coding and chat across its ...

Shortly after Hunter Lightman joined OpenAI as a researcher in 2022, he watched his colleagues launch ChatGPT, one of the fastest-growing products ever. Meanwhile, Lightman quietly worked on a team ...