At its 2025 Dev Day event, OpenAI unveiled a sweeping series of upgrades across ChatGPT, APIs, and developer tooling, signaling the company’s next evolution toward a fully integrated agent platform. The biggest announcement: users and developers can now build, run, and embed apps directly inside ChatGPT through a new Apps SDK, with launch partners including Canva, Figma, Spotify, and Zillow. Apps can open seamlessly in ChatGPT’s conversational interface, and monetization options will arrive later this year. OpenAI also introduced **AgentKit**, a toolkit for building custom AI agents with a visual workflow builder, embeddable chat components, evaluation tools, and connectors for data and APIs. The company confirmed that **GPT-5 Codex** is now generally available, including a Slack integration, SDK support for custom embedding in enterprise workflows, and expanded admin controls. Developers gain API access to **GPT-5 Pro**, **Sora 2**, and a new **realtime-mini** voice model that’s reportedly 70% cheaper and faster than prior versions. Analysts note that these updates push ChatGPT closer to acting as a browser-like hub — a unified interface where users can interact with external services entirely within conversations. The AgentKit and embedded apps framework may also intensify competition with automation platforms like Zapier, n8n, and Lindy. The announcements were made live during OpenAI Dev Day 2025, streamed on YouTube (link) and detailed further on the company’s site (Dev Day 2025). Additional reporting via TechCrunch: OpenAI launches apps inside ChatGPT.