---
title: "A2UI"
canonical: "https://canmyagentuse.com/specs/a2ui"
contentKind: "specification"
locale: "en"
description: "Streaming representation for generative user interfaces with stable and candidate specification tracks."
llmSummary: "A2UI defines a streaming JSON representation for generative UI. The 0.9.1 stable line and 1.0 candidate must not be conflated."
publishedAt: "2026-08-28T00:00:00.000Z"
updatedAt: "2026-08-28T00:00:00.000Z"
verifiedAt: null
tags: ["a2ui","ui","streaming","protocol"]
---

# A2UI

A2UI defines a streaming JSON representation for generative UI. The 0.9.1 stable line and 1.0 candidate must not be conflated.

- HTML: https://canmyagentuse.com/specs/a2ui
- JSON: https://canmyagentuse.com/api/v1/specs/a2ui.json
- Markdown: https://canmyagentuse.com/specs/a2ui.md

A2UI describes user interfaces as structured streamed data. It is a UI representation layer, distinct from tool protocols, agent-to-agent task exchange, and backend-to-application event protocols.

The catalog keeps the stable 0.9 line and the 1.0 candidate explicit. Renderer coverage, component vocabulary, transport, and extension behavior require revision-specific evidence.

## Revision identity

- Authority: A2UI project
- Revision: 0.9.1 stable / 1.0 candidate
- Maturity: mixed
- Structure: Streaming JSON UI schema
- Canonical specification: https://a2ui.org/specification/v0.9-a2ui/
- Roles: producer, renderer