A2UI v0.9: The New Standard for Portable, Framework-Agnostic Generative UI- Google Developers Blog

What this post added

A2UI v0.9 introduces a framework-agnostic standard for declaring UI intent, allowing agents to communicate with client applications using a common language. Key contributions include a shared web-core library for browser UI renderers, an official React renderer, version-bumped renderers for Flutter, Lit, and Angular, a dedicated spot for community renderers, and the A2UI Agent SDK for easier agent-side development with optimized generation pipelines and caching layers. New language features include client-defined functions, client-to-server data syncing, improved error handling, and a simplified schema. Transport interfaces have been refined for smoother agent-client connections (MCP, Websockets, REST, AG UI, A2A). The SDK supports version negotiation, dynamic catalogs, and resilient streaming for incremental parsing and healing of LLM output.