OpenAI launches SDK for building apps inside ChatGPT
At the OpenAI Dev Days keynote on October 6, 2025, CEO Sam Altman unveiled a new SDK preview that enables developers to create full apps integrated directly into ChatGPT conversations. The tool, built on the open-source Model Context Protocol, allows for interactive user interfaces and seamless app interactions within the chat window. Launch partners include Spotify, Canva, and Zillow, with more like Uber and DoorDash coming soon.
During the keynote, Altman explained that the SDK provides developers with 'full stack' control over app data, action triggers, and interactive user interfaces that appear inline in ChatGPT. 'To build real apps inside of ChatGPT,' he said, emphasizing the potential for developers already using the Model Context Protocol (MCP) to integrate by simply adding an HTML resource.
Demos highlighted practical applications. Software engineer Alexi Christakis demonstrated how the API exposes context from apps back to ChatGPT, likening it to the AI 'talking to apps.' In one example, ChatGPT expanded in real time on a Coursera video: 'I don't need to explain what I'm seeing in the video, ChatGPT sees it right away,' Christakis noted. Another demo showed ChatGPT generating Canva poster ideas while users consulted an inline Zillow map, with chat functionality persisting even in full-screen mode.
Altman also introduced an 'agentic commerce protocol' for instant checkout within ChatGPT, though monetization details will arrive 'soon.' Today's integrations feature Expedia and Booking.com alongside Spotify, Canva, and Zillow. Peloton, Target, Uber, and DoorDash will follow in coming weeks.
Developers can begin building with the SDK immediately, submitting apps for OpenAI review later this year. Compliant apps will appear in a directory, with top designs featured prominently.
The event also covered AgentKit, a GUI tool for creating custom chatbots, demonstrated by Christina Huang who built an 'Ask Froge' bot in under eight minutes using pre-built widgets. Minor updates included Slack integration for the Codex coding agent and new API access to models like Sora 2 and GPT5-Pro.