
C1 by Thesys is a Generative UI API that augments LLMs to respond with interactive UI like charts, forms, cards, and more in real-time, instead of plain text. It integrates seamlessly with any LLM, framework, or MCP in just 2 lines of code. Ship rich, interactive AI apps 10x faster with 80% less UI overhead.
Thesys is a Generative UI API middleware that transforms how AI applications communicate with users. Instead of returning plain text responses, Thesys augments large language models (LLMs) to generate interactive UI components like charts, forms, cards, tables, and slides in real time. It integrates with any LLM, framework, or MCP protocol using just two lines of code, allowing developers to ship rich, interactive AI experiences 10x faster while reducing UI overhead by up to 80%.
Thesys converts LLM responses into live, interactive interfaces on the fly. Users see charts, forms, cards, and reports appear instantly as the model generates them, making interactions far more engaging than scrolling through walls of text.
Add Thesys to any existing AI stack by changing the API endpoint URL and integrating the React SDK. The API is OpenAI-compatible, so it works with your current codebase, language, or framework without rewriting your application logic.
Every UI element generated by Thesys adapts to any screen size and can be styled to match your brand. Developers can also bring their own React components for custom logic, interactions, and styling, giving full control over the user experience.
Thesys offers zero data retention, SOC2 and ISO27001 compliance, GDPR alignment, and private deployment options. It supports all tool calls, connects to databases, documents, and APIs, and includes configurable actions, callbacks, and streaming for production-ready applications.
"83% of users find C1 responses more engaging compared to walls of text."
This statistic from Thesys's own research underscores the core value proposition: interactive UI dramatically improves user engagement. While most AI tools still output static text, Thesys turns every response into a live, explorable interface. Combined with the claim that teams build AI frontends 10x faster and 80% cheaper, the product offers a rare combination of improved user experience and reduced development cost.
You're building an AI-powered application where user engagement matters—whether it's a data analytics assistant, a customer support copilot, or an educational tool. If you're tired of wrestling with frontend code to make your AI responses look good, or if you want to differentiate your product with rich, interactive outputs without hiring a dedicated UI team, Thesys is worth a serious look. It's also a strong fit for teams that need enterprise compliance and want to avoid vendor lock-in, thanks to its open-source future and compatibility with any LLM or framework.
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