A2UI in Google products
Product support does not advance at the same speed as the protocol. Verify the host’s renderer version, registration path, and preview terms before building an integration.

Support matrix
| Product | Verified role | Important limit |
|---|---|---|
| Gemini Enterprise | Built-in native renderer for registered A2A agents | Current documentation states v0.8 support; managed ADK registration does not provide the same A2UI path |
| Google Chat | Workspace add-on quickstart using ADK and Vertex AI Agent Engine | Early Stage Public Preview |
| ADK Web | Developer UI capable of rendering A2UI agent parts | Current documented integration is based on the v0.8 basic catalog |
| Opal | A2UI-backed dynamic UI system for AI mini-apps | Product abstractions are higher level than the public wire protocol |
| Flutter GenUI | Cross-platform native renderer using A2UI underneath | Application owns transport setup; verify package and protocol compatibility |
Gemini Enterprise
Gemini Enterprise can send its supported catalog to an A2A agent, validate returned A2UI, and render the result in the host design system. The production lesson is version negotiation: do not send v0.9.1 messages to a host that advertises v0.8.
Only present actions the user is authorized to perform. Confirm destructive or financial actions outside the generated surface, and never place secrets in the A2UI data model.
Google Chat
The official quickstart connects a Chat app to an ADK agent hosted on Vertex AI Agent Engine. It is useful as a deployment reference for asynchronous progress, tool-backed data, and adaptive cards. Because the feature is preview, pin dependencies and maintain a text/card fallback.
Implementation checklist
- Record the exact renderer version advertised by the host.
- Negotiate A2UI and transport capabilities before generating UI.
- Version the catalog and examples sent to the model.
- Keep text fallback and error recovery paths.
- Test keyboard, screen reader, small viewport, slow network, and unsupported-component behavior in the real host.