OpenAI is set to unveil new features and updates for developers on the second day of its '12 Days of OpenAI' event. Anticipation surrounds potential API cost reductions and new developer tools, as indicated by various sources. The first day of the event featured announcements about enhancements to the API, including plans to integrate structured outputs and function calling capabilities, along with image understanding features. Sam Altman, CEO of OpenAI, hinted at significant developments for developers during a livestream, stating, 'we have a lot more stuff to come.' Expectations for Day 2 include updates to the o1 API, possible UI enhancements, and a reduction in prices for the GPT-4o model. The event aims to cater specifically to the developer community, with many looking forward to how these updates will impact their work.