● ONLINE
A2UI

open-source protocol for AI agents to generate secure, declarative UIs across platforms.

FreeDesign Systems
VISIT_WEBSITE >>

Product Overview

A2UI (a2ui.org) is Google's open-source project (Apache 2.0) for agent-driven interfaces, enabling AI agents to send declarative UI descriptions that clients render natively on web, mobile, and desktop. It uses a streaming JSON format for safe, incremental updates without code execution, supporting multi-agent systems, brand control, and cross-platform consistency with renderers for Angular, Flutter, React, and native. Secure Declarative UI: Agents send data; clients use pre-approved components to prevent attacks. LLM-Friendly: Flat structure for easy generation and progressive rendering. Cross-Platform: Renderers for web (React/Angular), mobile/desktop (Flutter/native). Interoperable: Open registry for custom components; transports like A2A for agent communication.

Best For

Teams building scalable, consistent digital products.

Key Features

  • Secure Declarative UI: Agents send data; clients use pre-approved components to prevent attacks.
  • LLM-Friendly: Flat structure for easy generation and progressive rendering.
  • Cross-Platform: Renderers for web (React/Angular), mobile/desktop (Flutter/native).
  • Interoperable: Open registry for custom components; transports like A2A for agent communication.

Pros

  • +Open source
  • +Comprehensive design system
  • +Frontend-ready components
  • +No coding required

Cons

  • -Adoption requires team alignment
  • -Customization can be complex

/// SPECS

  • Pricing:
    Free
  • Platform:
    Browser
/// Similar Tools
Flareum

Flareum

Design system builder that syncs Figma and code

Specify

Specify

Design token platform that pushes your design decisions to code — automatically

Zeroheight

Zeroheight

Living design system documentation — connect Figma to code with interactive docs

VKUI

VKUI

VK's open-source React library for consistent, accessible interfaces in VK apps and services.

VTEX Design System

VTEX Design System

open-source framework for consistent, accessible e-commerce interfaces.

Vaadin Design System

Vaadin Design System

open-source framework for consistent, accessible enterprise web apps with web components.

Vibe Design System

Vibe Design System

monday.com's open-source design system for consistent, accessible work management interfaces.

Watt Design System

Watt Design System

Holaluz's Figma-based UI kit for consistent, accessible renewable energy interfaces.