​
Introduction

Large Language Models (LLMs) are powerful tools for processing and generating text. However, when building AI-native applications, relying solely on text-based responses often limits user experience and functionality. Traditionally, transforming an LLM’s output into a rich, interactive user interface requires extensive manual coding on the UI. Generative UI is a paradigm shift where AI dynamically generates the user interface itself. Thesys provides C1 API and React SDK to bring Generative UI to your applications. With C1, you can send a natural language prompt, and the API will generate and stream live, interactive UI components directly into your client application.

​
See it in action

To understand how C1 works, consider a practical example. You can send a natural language prompt like the one below directly to the C1 API. c1-compare

Try it out live

Live interactive demo of C1 in action

​
Key Features

  • Interactive Components
    The generated UI is not static. C1 natively supports a range of interactive elements, including charts with tooltips, clickable elements that continue the conversation and forms that can capture user input to trigger subsequent actions.
  • Themeable
    The generated UI seemlessly adapts to your brand with a custom theme. Dark mode is supported out of the box.
  • Real-time UI Streaming
    C1 streams the UI as it’s generated, not after. This allows components to appear on the screen progressively, creating a more responsive and fluid user experience without waiting for the full response to be ready.
  • OpenAI-Compatible API
    The API is designed for seamless backend integration. By using the familiar OpenAI SDKs, you can adopt C1 with minimal changes to your existing code. On the UI, C1 React SDK replaces a traditional markdown renderer.
  • Robust Error Handling
    • LLM providers might go down but C1 won’t. C1 internally retries the request or routes to fallback providers, so your users are not affected.
    • LLM might generate incomplete or invalid response. C1 detects this and seemlessly fixes it in realtime.

​
What can I build with it

  • Analytics dashboards “Show me monthly revenue trends” → live line chart.
  • Conversational agents “Book me a flight and confirm details” → multi-step form in chat.
  • Internal tools “List all users who signed up in the last 30 days” → interactive table with line chart showing week-by-week growth.
  • E-commerce flows “Add this product to my cart and checkout” → interactive checkout UI.
  • Rebuilding AI agents with Generative UI Any existing AI agent - customer support bots, copilots, research assistants, or vertical-specific tools - can be reimagined with a Generative UI layer. Instead of limiting the agent to text-only interactions, C1 lets it generate forms, dashboards, and workflows that make the agent truly useful in production.