Make AI apps respond with interactive UI in real-time
C1 is a Generative UI API that augments LLMs to respond with interactive UI like charts, forms, cards, and more, in real time. It integrates seamlessly with any LLM, framework, or MCP in just 2 lines of code. Ship AI apps 10X faster with 80% less UI overhead.
👋 Hey folks, Parikshit here, co-founder of Thesys.
Thrilled to share what we’ve been building: C1, the world’s first Generative UI API 🚀
Most AI apps are still stuck in the terminal era, type a prompt, get a wall of text.
It works, but it’s primitive. AI is unlocking infinite user journeys, but most UIs are static and hardcoded. We built C1 so the interface can finally keep up with the intelligence behind AI-native products.
What is C1?
C1 is an API middleware that augments LLMs to respond with live, interactive UI like forms, charts, cards, dashboards instead of plain text.
What can C1 do?
➡️ One-line setup: npx create-c1-app
➡️ Works with any AI stack (OpenAI-compatible, any framework or MCP)
➡️ Customizable and responsive to your brand
➡️ Supports all tool-calls (databases, documents, APIs)
➡️ Configurable actions, callbacks, and workflows out of the box
➡️ Handles streaming, error states, and production-ready UI flows
➡️ Plug in your own React components with state, logic, and validation
Why does it matter?
✅ Ship interactive AI apps 10x faster
✅ Cut 80% of frontend maintenance costs
✅ Create experiences 83% of users prefer
From copilots to dashboards, e-commerce to search, C1 turns model responses into production-ready interfaces, no manual wiring required.
🎁 Launch bonus : Up to 5M tokens free if you sign up in the next 24 hours.
“Make AI apps respond with interactive UI in real-time”
C1 by Thesys launched on Product Hunt on September 30th, 2025 and earned 635 upvotes and 108 comments, earning #3 Product of the Day. C1 is a Generative UI API that augments LLMs to respond with interactive UI like charts, forms, cards, and more, in real time. It integrates seamlessly with any LLM, framework, or MCP in just 2 lines of code. Ship AI apps 10X faster with 80% less UI overhead.
On the analytics side, C1 by Thesys competes within API, Developer Tools and Artificial Intelligence — topics that collectively have 1.1M followers on Product Hunt. The dashboard above tracks how C1 by Thesys performed against the three products that launched closest to it on the same day.
Who hunted C1 by Thesys?
C1 by Thesys was hunted by Kevin William David. A “hunter” on Product Hunt is the community member who submits a product to the platform — uploading the images, the link, and tagging the makers behind it. Hunters typically write the first comment explaining why a product is worth attention, and their followers are notified the moment they post. Around 79% of featured launches on Product Hunt are self-hunted by their makers, but a well-known hunter still acts as a signal of quality to the rest of the community. See the full all-time top hunters leaderboard to discover who is shaping the Product Hunt ecosystem.
Kevin William David
👋 Hey folks,
Parikshit here, co-founder of Thesys.
Thrilled to share what we’ve been building: C1, the world’s first Generative UI API 🚀
Most AI apps are still stuck in the terminal era, type a prompt, get a wall of text.
It works, but it’s primitive. AI is unlocking infinite user journeys, but most UIs are static and hardcoded. We built C1 so the interface can finally keep up with the intelligence behind AI-native products.
What is C1?
C1 is an API middleware that augments LLMs to respond with live, interactive UI like forms, charts, cards, dashboards instead of plain text.
What can C1 do?
➡️ One-line setup: npx create-c1-app
➡️ Works with any AI stack (OpenAI-compatible, any framework or MCP)
➡️ Customizable and responsive to your brand
➡️ Supports all tool-calls (databases, documents, APIs)
➡️ Configurable actions, callbacks, and workflows out of the box
➡️ Handles streaming, error states, and production-ready UI flows
➡️ Plug in your own React components with state, logic, and validation
Why does it matter?
✅ Ship interactive AI apps 10x faster
✅ Cut 80% of frontend maintenance costs
✅ Create experiences 83% of users prefer
From copilots to dashboards, e-commerce to search, C1 turns model responses into production-ready interfaces, no manual wiring required.