OpenUI
Framework-agnostic generative UI framework with a compact streaming language and runtimes for React, Vue, Svelte and Angular.
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Use cases
About OpenUI
OpenUI is listed in our frameworks category and is aimed at builders. Framework-agnostic generative UI framework with a compact streaming language and runtimes for React, Vue, Svelte and Angular. Pricing, as the maker states it: Free and open source (MIT). Maturity: Mature. We last checked the official link on 2026-10-20.
What is OpenUI?
OpenUI, from Thesys, is an open-source, framework-agnostic generative UI framework. Its centerpiece is OpenUI Lang, a compact, streaming-first language for model-generated interfaces that, by the maker's figures, uses up to 67% fewer tokens than JSON.
You define the components a model may use, OpenUI generates the prompt instructions from that library, and a streaming renderer draws the UI progressively as tokens arrive. A framework-agnostic core powers runtimes for React, Vue, Svelte and Angular, and React also gets built-in component libraries (charts, forms, tables, layouts) and ready-made chat interfaces. The project notes it has no official cryptocurrency or token.
Sources: the official README and our directory listing, checked 2026-10-20. Official site: openui.com.
Who is OpenUI for?
Developers building AI assistants, copilots or agent apps that should answer with real interface elements instead of plain text.
OpenUI at a glance
- Open source: Yes (MIT License)
- GitHub: thesysdev/openui · 12,815 stars (as of Oct 21, 2026)
Key features
- OpenUI Lang: compact, streaming-first UI language
- Prompt instructions generated from your component library
- Streaming renderer for React, Vue, Svelte and Angular
- Built-in charts, forms, tables and chat interfaces for React
- Playground and scaffold CLI
OpenUI FAQ
What is OpenUI?
OpenUI, from Thesys, is an open-source, framework-agnostic generative UI framework. Its centerpiece is OpenUI Lang, a compact, streaming-first language for model-generated interfaces that, by the maker's figures, uses up to 67% fewer tokens than JSON.
Who is OpenUI for?
Developers building AI assistants, copilots or agent apps that should answer with real interface elements instead of plain text.
Is OpenUI free?
OpenUI's pricing, as the maker states it: Free and open source (MIT). Check the official site for current plans.
Is OpenUI open source?
Yes. OpenUI is released under the MIT License, according to its GitHub repository.
What are alternatives to OpenUI?
Similar tools include Agno, CopilotKit, Tambo, assistant-ui, Atmosphere and FrontierAgent.
OpenUI ratings and reviews
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OpenUI alternatives
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CopilotKit
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Tambo
Generative UI SDK for React that lets agents render components.
assistant-ui
Open-source React components and runtimes for building AI chat and agent front ends with streaming, tools and persistence.
Atmosphere
Real-time AI agent runtime for the JVM that runs one agent class on Spring AI, LangChain4j and other backends with streaming, MCP, A2A and AG-UI.
FrontierAgent
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Related lists
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💲 Estimate API cost: compare per-request and monthly costs for GPT, Claude, Gemini and Grok models.
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