Reverse-engineering ChatGPT's Intelligent UI: DIL language, server-side compilation and sandboxed runtime
rohanpaul_ai · x · 2026-10-12
A new post reverse-engineers ChatGPT's Generative UI (rebranded Intelligent UI) and explains how it actually works:
- The model never writes raw code — it emits a custom UI language called DIL (mixing Markdown, JSX, and JS syntax)
- Server-side compilation repairs partial output, validates component properties, and hoists text into constants, streaming out a JS program plus JSON data
- The client runs it in a sandboxed iframe + Web Worker, keeps state, diffs the tree, and renders with 70 native components
- Interactions require no additional AI calls — user events map to callbacks, making the UI feel fast and native
In short: the model writes DIL, the server compiles it, and the client executes it against a shared design-system catalog of components and tokens.
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