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Thesys

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Augment LLMs to respond with interactive UI in real-time instead of text.

Developer ToolsAI AssistantsUI/UX Design
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Tracked since2026
0 reviews tracked

The Bottom Line

Entry price

Free plan available, paid tiers above

Biggest pro

Significantly improves user engagement compared to text-only responses.

Biggest con

LLM tokens are billed separately, adding to the overall cost.

TL;DR - Thesys

  • Transforms LLM text responses into interactive UI components in real-time.
  • Accelerates AI frontend development and enhances user engagement.
  • OpenAI-compatible API, works with various LLMs and supports custom components.
Pricing: Free plan available
Best for: Growing teams

What is Thesys?

Editorial review
Thesys offers C1, an API middleware that transforms large language model (LLM) text responses into dynamic, interactive user interfaces. Instead of receiving plain text, AI applications can respond with structured UI components like charts, forms, cards, lists, tables, slides, and reports, rendered in real-time. This allows developers to build AI-powered applications with rich, adaptive frontends without extensive manual UI coding. C1 is designed for AI-native teams building agents, copilots, and tools where use cases evolve rapidly and static UIs are insufficient. It integrates as an OpenAI-compatible endpoint, working with various LLMs (OpenAI, Anthropic, Google) and allowing for custom React components and branding. The platform aims to accelerate AI frontend development, improve user engagement, and provide enterprise-grade security and compliance. The product's core value lies in enabling AI applications to deliver engaging, context-aware, and personalized user experiences by dynamically generating UI based on LLM outputs, adapting to logic, state, and user behavior.

Available on: Web

how we evaluateSourcethesys.dev ↗

Pros & Cons

Pros

  • Significantly improves user engagement compared to text-only responses.
  • Accelerates AI frontend development by up to 10x and reduces costs by 80%.
  • Provides a flexible and adaptive UI that responds dynamically to user intent and context.
  • Compatible with existing AI stacks and various LLMs, preventing vendor lock-in.
  • Offers robust security and compliance features for enterprise use.

Cons

  • LLM tokens are billed separately, adding to the overall cost.
  • Requires integration with a React SDK, which might be a barrier for non-React users.
  • Artifacts API is billed separately from core C1 API calls.

Preview

Key Features

Generates interactive UI components (charts, forms, cards, lists, tables, slides, reports) from LLM responses.OpenAI-compatible API endpoint for easy integration.Supports multiple LLMs including OpenAI, Anthropic, and Google.React SDK for rendering generated UI.Customizable UI to match brand and design systems.Supports all tool-calls for connecting to external data (databases, documents, APIs).Allows integration of custom React components with custom logic and styling.Configurable actions, callbacks, and workflows.

Pricing Plans

Pricing checked Jul 16, 2026

Free

$0 / month

  • Free credits for developers exploring Generative UI
  • 5K C1 API calls / month
  • Upgrade for additional usage
  • LLM credits worth $10 free
  • Style customizations
  • Supports all popular LLMs
  • Discord Community support

Build

$49 / month

  • Usage-based plan for teams ready to ship with GenUI.
  • 25K C1 API calls / month
  • $0.002 per call after that
  • Everything in Free
  • Higher request priority
  • Higher rate limits
  • Email Support

Grow

$499 / month

  • Usage-based plan for teams ready to ship with GenUI.
  • 500K C1 API calls / month
  • $0.001 per call after that
  • Everything in Build
  • Highest request priority
  • Highest rate limits
  • Priority Slack Support
  • Dedicated Solutions engineer (Add-on)

Scale

Contact sales

  • Secure deployments for large orgs with scaled needs.
  • Everything in Grow
  • Self-hosting or VPC deployment options
  • Custom rate limits and usage controls
  • SOC2, HIPAA, and compliance support
  • Enterprise-grade SLAs & uptime guarantees
  • Bring your own LLM key (On Request)
  • Support SLAs
Calculate your costView full pricing

Is Thesys worth the price?

75/100

Thesys offers a fair pricing structure, especially with its generous Free tier providing 5K API calls and $10 in LLM credits.

The Build tier at $49/month for 25K calls is competitive for small teams, though the per-call overage of $0.002 can add up. The Grow tier at $499/month for 500K calls offers better value for scaling teams with a lower overage cost.

This pricing is best for developers and startups looking to integrate interactive UI into their LLM applications, with clear paths for growth.

Hidden Costs & Gotchas

Overage fees for C1 API calls

Dedicated Solutions engineer is an add-on

SSO SAML is 'Coming Soon'

Bring your own LLM key is 'On Request'

How Thesys Compares to Competitors

Compared to platforms like Vercel or Netlify for UI deployment, Thesys focuses specifically on interactive UI for LLMs. While direct pricing comparisons are difficult due to different service offerings, Thesys's $49/month Build tier for 25K API calls seems reasonable for its specialized service, whereas general cloud providers might offer broader compute at similar price points but without the GenUI focus. For enterprise needs, the 'Contact Sales' model for Scale is standard, similar to many enterprise SaaS solutions.

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Thesys FAQ

How does Thesys enhance AI assistant capabilities?

Thesys transforms large language model text responses into dynamic, interactive user interfaces, allowing AI assistants to respond with structured UI components like charts, forms, or tables. This enables AI applications to deliver engaging, context-aware, and personalized user experiences beyond plain text.

What kind of user benefits most from Thesys?

Thesys is designed for AI-native teams building agents, copilots, and tools where use cases evolve rapidly and static UIs are insufficient. It accelerates AI frontend development and improves user engagement by dynamically generating UI based on LLM outputs.

How does Thesys compare to OpenUI?

Thesys offers C1, an API middleware that transforms LLM text responses into interactive UIs, accelerating AI frontend development by up to 10x. Both tools aim to generate UIs, but Thesys focuses on dynamic, real-time UI generation from LLM outputs to prevent vendor lock-in with its compatibility across various LLMs.

What are the main trade-offs when using Thesys?

A primary trade-off is that LLM tokens are billed separately, which adds to the overall cost of implementation. Additionally, Thesys requires integration with a React SDK, which might pose a barrier for development teams not utilizing React.

How is Thesys priced?

Thesys offers a free tier for users to get started. For more extensive usage and additional features, paid plans are available.

Can Thesys integrate with existing AI development stacks?

Yes, Thesys integrates as an OpenAI-compatible endpoint, allowing it to work with various large language models such as OpenAI, Anthropic, and Google. This compatibility helps prevent vendor lock-in and allows for custom React components and branding.

How does Thesys handle user interface customization?

Thesys allows developers to integrate custom React components and branding into the dynamically generated user interfaces. This ensures that the interactive UIs align with specific application requirements and brand guidelines.

Source: thesys.dev

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