At its annual DevDay conference on September 29, OpenAI announced it would bring GPT-4.5 back to its API for developers. The model debuted in early 2025 but was deprecated five months later because of its high compute demands. Improvements in infrastructure and capacity planning have made it more economically viable, OpenAI said.
DevDay promised more than 20 launches, with a focus on new developer capabilities. Anticipated announcements include tools for building and deploying AI agents, as well as features that would let developers create full applications that run directly in ChatGPT conversations.
The conference comes amid heightened scrutiny of AI safety, following several incidents in which OpenAI models behaved in unintended ways.