A comprehensive developer tutorial covering A2UI – a declarative protocol for AI agents
to generate native UIs via JSON messages.
Technical highlights:
- Adjacency list model (flat component list with ID refs) instead of nested trees –
designed for LLM streaming and incremental generation
- Data binding via JSON Pointer paths (RFC 6901) for reactive updates without component
regeneration
- Three-layer architecture: UI structure (surfaceUpdate), application state
(dataModelUpdate), client rendering
- Transport-agnostic: works with A2A Protocol, SSE, WebSockets, or AG UI
The tutorial includes:
- Step-by-step agent setup with Python ADK (code examples included)
- Client implementation guides for Lit, Angular, and Flutter renderers
- Message processing & state management implementation checklist
- Custom component catalog creation
- Error handling and validation patterns
Production use: Google's Opal, Gemini Enterprise, Flutter GenUI SDK.
React renderer coming Q1 2026. Full spec and samples on GitHub.
GitHub: https://github.com/google/a2ui
