OpenAI DevDay 2025: ChatGPT Now an AI Operating System

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OpenAI’s third DevDay, held in San Francisco on October 6, 2025, was a historic moment. At the event, CEO Sam Altman announced that ChatGPT was no longer just a chatbot, but a full-fledged AI operating system – allowing developers to directly build powerful AI apps and agents.

Today, ChatGPT has over 800 million weekly users and 4 million developers actively working on it. Together, this marks the beginning of a new era in AI.

New AI App Ecosystem

The main focus of this DevDay was to provide developers with the tools they need to create powerful and integrated AI experiences – directly within ChatGPT.

1. ChatGPT becomes an OS + Apps SDK launch

The biggest announcement was the launch of ChatGPT Apps and the Apps SDK.

  • ChatGPT Apps: ChatGPT has now become an application environment. This means third-party services (like Canva, Spotify, Expedia) will now run directly within ChatGPT – without having to open a separate site or app.
  • Apps SDK: A new toolkit for developers to create custom apps that connect to external data, perform actions, and display interactive UIs within ChatGPT chats.

Launch Partners: Booking.com, Canva, Coursera, Expedia, Figma, Spotify, and Zillow – all have integrated their apps into ChatGPT.

All of this is based on the Model Context Protocol (MCP), which gives Chatgpt agent-like control and backend access.

2. AgentKit: Production-ready AI Agents

OpenAI also launched AgentKit – a complete toolkit that allows developers to build and deploy powerful AI agents.

  • Agent Builder: A simple visual tool to design, test, and launch agents with a drag-and-drop interface.
  • ChatKit: A ready-made ChatGPT-style chat interface for embedding custom agents.
  • Evals: A testing system to test agent performance and analyze step-by-step decision-making.

Model and API Updates

DevDay also brought major updates to models and APIs:

  • GPT-5 Pro API: New flagship model that is 40% faster and more efficient for real-time applications.
  • Codex (GA): The AI model for coding is now based on GPT-5 and adjusts its “think time” according to the complexity of the task.
  • Sora 2 & Sora 2 Pro: New video generation models that let developers integrate video creation into their apps.
  • GPT-Realtime-Mini & GPT-Image-1-Mini: Lighter, cheaper models – the image model is 80% cheaper than the previous version.

Strategic Partnerships and Future Vision

  • AMD Partnership: OpenAI has signed a multi-billion dollar deal with AMD that will provide up to 6 GW of next-gen GPUs – to boost AI infrastructure.
  • AI Device Vision: Sam Altman and former Apple design chief Jony Ive are working together on new AI-powered devices that will be more “peaceful” and “less anxious” than phones or laptops.

OpenAI DevDay 2025 demonstrated the company’s goal to build a complete infrastructure for AI. By transforming ChatGPT into an AI Operating System By making it easy for everyone to build AI agents through AgentKit OpenAI has taken major steps toward making AI a core technology for every user and business.

Watch the official keynote video: OpenAI DevDay 2025: Opening Keynote with Sam Altman

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