How Does Thesys C1 Differ From AI Code Generators Like Lovable Or Bolt?

AI code generators produce static UI code before an app runs. Thesys C1 generates and renders live, context-aware UI components at runtime, adapting to each user query and application state in real time. C1 is the interface itself, not a code authoring tool.

What LLM Providers Are Compatible With Thesys C1 API?

C1 works with all major LLM providers out of the box, including OpenAI (GPT-5), Anthropic (Claude Sonnet 4), and Google (Gemini 3 Pro and Flash). The API uses an OpenAI-compatible endpoint format, so switching between models requires no code changes.

Can Thesys C1 Be Customized To Match A Brand Design System?

Yes. C1 is built on top of Crayon, an open-source UI component library. Developers can apply custom themes, tokens, colors, and component overrides so that all generated UI outputs match the host application's existing brand identity and design language.

What Is The Difference Between C1 Embed And C1 Visualize Endpoints?

The Embed endpoint is a drop-in replacement for standard LLM chat completion calls, supporting tool calling and conversation history. The Visualize endpoint takes a raw data object and returns the optimal UI representation for it, without tool calling support.

How Does The Thesys Agent Builder Work Without Code?

Agent Builder lets users connect data sources like files, URLs, or databases, set natural language instructions for tone and guardrails, and publish a live agent as an embeddable widget or standalone page. All generated responses render as interactive UI components rather than plain text.

Thesys

Name: Thesys
Availability: InStock
Author: Thesys, Inc.

by Thesys, Inc. • San Francisco, California, USA • Founded 2024

Generative UI API Turning LLM Responses Into Live Interfaces

No reviews yet

170 9

generative ui api middleware ai agents developer tools react sdk

Visit Thesys

Follow:

Trust Score

Based on ratings & reviews

4.3 /5

47 reviews

170

Views

Clicks

Pricing

From $49/mo

What is Thesys?

Thesys is an API middleware platform that augments large language models to respond with interactive UI components in real time instead of plain text. Its flagship product, C1, acts as an API layer on top of LLMs from OpenAI, Anthropic, and Google, converting model outputs into live, adaptive interfaces including charts, forms, tables, cards, and layouts. The C1 React SDK renders these components directly in the browser. Thesys supports tool calling for external data fetching, custom design system theming via the open-source Crayon UI library, and streaming responses for real-time rendering.

The platform also offers an Artifacts API for generating slides and reports within applications, and Agent Builder, a no-code tool for creating and publishing AI agents that respond with interactive UI. Developers integrate C1 in as few as two lines of code, making it compatible with any existing AI stack, framework, or MCP server. Thesys targets engineering teams building AI-native products where static chat interfaces fall short, serving use cases from enterprise analytics dashboards to customer-facing copilots and internal tooling.

Thesys — Generative UI API Turning LLM Responses Into Live Interfaces Whether you're evaluating Thesys for your team or comparing it to alternatives in the AI Code Tools category, this in-depth review covers everything: features, pricing, real user reviews, pros and cons, integrations, and direct comparisons against competitors.

Key Features 8

Generative UI API That Converts LLM Responses Into Interactive Interfaces

No-Code Agent Builder to Create and Publish AI Apps Instantly

Real-Time Rendering of Charts, Tables, Forms, and Cards

Multi-LLM Support Including OpenAI, Anthropic, and More Providers

Customizable Themes and Branding to Match Your Design System

Seamless Data Integration via File Uploads, URLs, and Databases

Enterprise-Grade Private Deployment With Full Security and Compliance

Embeddable AI Copilots and Standalone Apps With One-Click Publishing

Who Is Thesys For

1 Full-Stack AI Developers

2 SaaS Product Engineers

3 AI Agent Builders

4 Enterprise Analytics Teams

5 Startup Technical Founders

6 DevTool Architects

Pros & Cons

Pros 4 benefits

Two-Line SDK Integration
Multi-LLM Provider Compatibility
Open-Source Crayon Component Library
Real-Time Adaptive UI Rendering

Cons 3 limitations

React-Only SDK Currently Available
LLM Token Costs Billed Separately
Early-Stage Enterprise Compliance Features

Frequently Asked Questions

5 questions

How Thesys works

Thesys is positioned as generative UI API Turning LLM Responses Into Live Interfaces. Under the hood it ships 8 headline capabilities, including Generative UI API That Converts LLM Responses Into Interactive Interfaces, No-Code Agent Builder to Create and Publish AI Apps Instantly, Real-Time Rendering of Charts, Tables, Forms, and Cards, Multi-LLM Support Including OpenAI, Anthropic, and More Providers, Customizable Themes and Branding to Match Your Design System and Seamless Data Integration via File Uploads, URLs, and Databases. Together these features cover the core workflows most teams expect from a modern ai code tools, from initial setup through day-to-day production use.

Thesys runs as a self-contained product, so you can adopt it without touching the rest of your stack — useful when you want to evaluate the tool in isolation before wiring up integrations.

Who is Thesys for?

Thesys is most useful for Full-Stack AI Developers, SaaS Product Engineers, AI Agent Builders and Enterprise Analytics Teams. If your team falls into one of those buckets, the feature set lines up well with how you already work — you won't be forcing a square peg into a round hole.

Beyond the obvious use case, the product tends to attract users who want a low-friction starting point option in the ai code tools space.

Thesys pricing explained

Thesys runs on a freemium model. You get a usable free tier to evaluate the product, and you only pay when you outgrow the limits — usage volume, seat count, or premium features. Headline pricing: From $49/mo.

Across the AI Gear Base rubric, we score freemium pricing models on transparency, rate-limit honesty, and how predictable spend is at scale. Thesys's freemium approach is standard for the category — useful for evaluation, but always re-check tier limits before you depend on the free plan.

Our verdict on Thesys

Thesys hasn't been rated by enough reviewers yet to publish an aggregate score. The strongest signal in those reviews is that two-line sdk integration. The most common complaint is that react-only sdk currently available — worth knowing before you commit, but rarely a deal-breaker for teams that already match the use case.

If you're evaluating Thesys against alternatives, weigh it on the same 7-criteria rubric we apply to every tool: capability, integrations, pricing transparency, support, security posture, roadmap velocity, and community signal. Built by Thesys, Inc., founded in 2024, the product has a clear track record you can verify before adopting it. The bottom line: Thesys is a solid pick in the ai code tools category, and it deserves a spot on your shortlist if your workflow matches what it was built for.

What's New

monthly

Agent Builder Launch

No-code agent builder for creating and publishing AI apps that respond with charts, forms, cards, and interactive UI. Ranked #2 Product of the Day on Product Hunt.

Feb 10

C1 Artifacts API

New API endpoint enabling AI apps to generate stunning slides and reports in real time, integrable in three steps or usable as an MCP tool.

Nov 11

User Base

1K+ developers

Active Users

Security & Privacy

US (AWS North Virginia)

SOC 2 (Enterprise plan) HIPAA (Enterprise plan) GDPR Compliant

API key-based authentication SSL/TLS encryption SSO/SAML support (Coming Soon) Self-hosting and VPC deployment (Enterprise) Bring your own LLM key (Enterprise)