Feature Comparison
OpenUI vs json-render (Vercel), A2UI (Google), and CopilotKit OpenGenerativeUI.
The Generative UI Landscape
Four frameworks. Which one ships to production?
At a Glance
| OpenUI | json-render (Vercel) | A2UI (Google) | CopilotKit OpenGenUI | |
|---|---|---|---|---|
| Tokens | 1x | 3x | 3x | 4x |
| Latency (60 tok/s) | 4.9s | 14.2s | 14.2s | ~20s |
| Streaming | Yes | Yes | Yes | Partial |
| Consistent output | Yes | Yes | Yes | No |
| Design system | Yes | Yes | Yes | No |
| Components | Library + custom | Library + custom | Custom only | None |
| Built-in data fetching | Yes | No | No | No |
| Chat UI included | Yes | No | No | Yes |
| Multi-platform | Web, mobile, email | Web, mobile, PDF, email, video | Web, iOS, Android | Web |
| Security risk | Minimal | Minimal | Minimal | Medium |
| License | MIT | Apache 2.0 | Apache 2.0 | MIT |
Best For
- Data-driven chat UIs and dashboards → OpenUI
- One UI across web, mobile, PDF and email → OpenUI
- Multi-agent systems across iOS, Android, and web → OpenUI
- Creative one-off visuals (animations, generative art) → CopilotKit OpenGenUI