OpenAI DevDay 2025 marked the start of the "agentic era" of software development, focusing on making it "easier to build with AI" and transitioning AI from a "chatbot" into a "doer". We break down the revolutionary AgentKit, featuring Agent Builder, a visual, drag-and-drop platform launched to help developers rapidly deploy multi-step AI agents from prototype to production. We also discuss the new Apps SDK for seamlessly integrating third-party services into ChatGPT and the debut of powerful models like GPT-5 Pro and Sora 2, signifying that software development now takes minutes, not months.