Thesys offers C1, a Generative UI API that transforms LLM responses (OpenAI, Anthropic, Gemini…) into interactive UI components: forms, tables, charts, and dynamic layouts. OpenAI-compatible, C1 integrates with any framework via its React SDK. The C1 Artifacts API enables generation of slides and complete reports directly in your applications. A no-code Agent Builder is also available to create agents that respond with UI rather than plain text. The freemium model with $10 in credits offered upon signup makes getting started accessible.
What is Thesys?
The essentials
C1 by Thesys is an LLM endpoint compatible with the OpenAI standard, designed to return structured UI components rather than plain text. When an agent uses C1, its responses are automatically transformed into React components rendered via the official SDK. The tool connects to external data through standard tool calls — databases, documents, REST APIs — ensuring interfaces are always fed by fresh data. A no-code Agent Builder allows prototyping agents without writing code.
Key features
C1 offers several key capabilities. Dynamic UI component generation includes interactive forms, data tables, analytical charts, and complex layouts generated in real-time. The OpenAI-compatible endpoint enables quick migration from existing LLM integrations. The C1 React SDK simplifies component rendering on the client side. The C1 Artifacts API enables creation of complete slides and reports integrated into applications. The no-code Agent Builder allows creating and testing agents visually without writing code. Finally, the platform is compatible with all major LLMs on the market.
Use cases
Thesys applies to many scenarios. Internal analytics tools can display dynamically generated dashboards based on user questions. AI CRMs can present enriched customer profiles in response to sales requests. Educational platforms can generate interactive exercises on the fly. Reporting tools can automatically create presentations from raw data, significantly reducing preparation time.
Advantages
The main advantage of Thesys is dramatically improving the user experience of AI applications: instead of reading a paragraph of text, the user interacts with data presented visually. For developers, integration is minimal thanks to existing OpenAI compatibility. The pay-as-you-go model avoids high fixed costs in the startup phase, and 100 free artifacts pages per month allows moderate usage without fees.
Pricing
Thesys offers an Essentials plan at $0 with $10 in credits offered upon signup, no credit card required. The C1 Artifacts API offers 100 free pages per month, then $0.01 per operation. Billing is then entirely usage-based, with no mandatory monthly subscription. An Enterprise plan with private deployment, enterprise SLA, SOC2/GDPR/ISO 27001 compliance, and a dedicated engineer is available upon request.
Conclusion
Thesys represents a promising technology building block for developers who want to evolve their AI agents toward rich conversational interfaces. Its accessible freemium positioning, universal compatibility with LLMs, and React SDK make it a serious option for any project looking to go beyond the text chatbot.