Build Hour: Responses API

The Responses API is our flagship API for building agents. This Build Hour shows how the Responses API unlocks persistent reasoning, hosted tools, and multimodal workflows for GPT-5. Steve Coffey (API Engineering) covers: • How to use built-in tools, call multiple tools in one API request, and preserve reasoning tokens across turns • How the Responses API is faster and more cost-efficient • Live demo: building a simulator to bring a day in the life of an OpenAI engineer to life • Live Q&A 👉 Follow along with the code repo: https://github.com/openai/build-hours 👉 Responses API Docs: https://platform.openai.com/docs/api-reference/responses 👉 Migrate to Responses API Guide: https://platform.openai.com/docs/guides/migrate-to-responses 👉 Sign up for upcoming live Build Hours: https://webinar.openai.com/buildhours/