# AG-UI review

> AG-UI is an open, event-based protocol that standardizes how AI agents connect to user-facing frontend applications.

Devtoolwatch Board, the week of Oct 25–31, 2026. Canonical page: https://index.devtoolwatch.com/tools/ag-ui/

## TL;DR

AG-UI is an open, lightweight, event-based protocol for connecting agent backends to user-facing applications. It is for developers adding agent features such as streaming chat, shared state and generative UI to frontends. It works with any event transport and integrates with frameworks including LangChain, CrewAI, Google ADK, Mastra and Pydantic AI.

## AG-UI at a glance

- **Category:** [Agent frameworks](https://index.devtoolwatch.com/categories/agent-frameworks/)
- **Maintained by:** ag-ui-protocol (organization, [@ag-ui-protocol](https://github.com/ag-ui-protocol) on GitHub)
- **License:** MIT
- **Language:** TypeScript, Python, C#
- **Repository:** [github.com/ag-ui-protocol/ag-ui](https://github.com/ag-ui-protocol/ag-ui)
- **Website:** [ag-ui.com](https://ag-ui.com)
- **npm package:** [@ag-ui/core](https://www.npmjs.com/package/@ag-ui/core) 1.0.3
- **Latest release:** [release/2026-10-21](https://github.com/ag-ui-protocol/ag-ui/releases/tag/release/2026-10-21) on GitHub, Oct 21, 2026
- **First published:** May 7, 2025

## What AG-UI does

- AG-UI defines about 16 standard event types that agent backends emit during execution.
- AG-UI supports real-time agentic chat with streaming and bi-directional state synchronization between agent and app.
- AG-UI supports generative UI, structured messages, frontend tool integration and human-in-the-loop collaboration.
- AG-UI includes a middleware layer that works with any event transport, such as SSE, WebSockets or webhooks.
- AG-UI ships with a reference HTTP implementation and a default connector.
- AG-UI offers SDKs in TypeScript, Python and .NET, plus community SDKs for Kotlin, Go, Dart, Java, Rust, Ruby and C++.

### How it works

AG-UI sits between an agent runtime and a frontend. Agent backends accept simple AG-UI-compatible inputs and emit AG-UI events over a transport of your choice. A middleware layer allows loose event format matching. Clients such as CopilotKit, terminal apps, Slack, Microsoft Teams and React Native consume the events. Framework integrations are published as separate packages, such as @ag-ui/aws-strands.

## How to install AG-UI

**Create a new app with npx**

```
npx create-ag-ui-app my-agent-app
```

**Core package with npm**

```
npm install @ag-ui/core@1.0.3
```

**Google ADK integration with pip**

```
pip install ag_ui_adk==0.10.0
```

### Requirements

- Node.js with npm or npx for the TypeScript packages and app scaffolding.
- The ag_ui_adk 0.10.0 Python package requires Python below 3.16.
- The @ag-ui/spring-ai 0.0.4 package requires @ag-ui/core and @ag-ui/client 1.0.0 or later.

### First steps

1. Scaffold an AG-UI application with the create-ag-ui-app command.
2. Browse the AG-UI Dojo for focused examples of core building blocks, each 50-200 lines of code.
3. Follow the applications quickstart in the AG-UI docs to build an AG-UI-powered app.

## Who AG-UI is for

- Developers adding agent chat, shared state or generative UI to user-facing applications.
- Teams using LangChain, CrewAI, Google ADK, Mastra, Pydantic AI, LlamaIndex or AWS Strands agents.
- Developers who need a frontend-agent connection independent of a specific transport.

### Limitations

- AG-UI only covers agent-user interaction. Tool access (MCP) and agent-to-agent communication (A2A) are separate protocols.
- Some integrations, including AWS Bedrock Agents, OpenAI Agent SDK, Nim, Flowise and Langflow, are still in progress.
- The Spring AI integration caps the protocol at 0.0.39 and drops images, audio, video and documents, because the community Java SDK is not on 1.0.

## Usage data (the week of Oct 25–31, 2026)

- Board rank: #64 overall, #4 in Agent frameworks, momentum score 73
- Downloads that week: 4.6M (+45% vs 4-week average)
- New GitHub stars per week (last 12 weeks): Aug 9: 142; Aug 16: 177; Aug 23: 135; Aug 30: 123; Sep 6: 125; Sep 13: 100; Sep 20: 110; Sep 27: 242; Oct 4: 155; Oct 11: 223; Oct 18: 149; Oct 25: 156

## AG-UI alternatives

| Rank | Tool | Stars | Downloads/wk |
|---|---|---|---|
| #1 | [Harness²](https://index.devtoolwatch.com/tools/google-research-harness2/) | 21.7k | – |
| #2 | [HyperFrames](https://index.devtoolwatch.com/tools/heygen-com-hyperframes/) | 76.6k | 1.5M |
| #3 | [AgentScope](https://index.devtoolwatch.com/tools/agentscope-ai-agentscope/) | 35k | 51.4k |
| #5 | [LangGraph](https://index.devtoolwatch.com/tools/langgraph/) | 44.2k | 18.5M |
| #6 | [Bifrost](https://index.devtoolwatch.com/tools/maximhq-bifrost/) | 9.3k | – |
| #7 | [assistant-ui](https://index.devtoolwatch.com/tools/assistant-ui/) | 12.9k | 2.8M |

## AG-UI FAQ

### Is AG-UI free and open source?

Yes. AG-UI's source code is on GitHub (ag-ui-protocol/ag-ui) under the MIT license, so you can use it for free.

### How do I install AG-UI?

Run `npx create-ag-ui-app my-agent-app`. The install section above has the other options from the project's README.

### Is AG-UI still maintained?

Yes. The ag-ui-protocol/ag-ui repository was last updated on Oct 21, 2026, and the latest release, release/2026-10-21 on GitHub, came out on Oct 21, 2026.

### How popular is AG-UI?

AG-UI has 16.9k GitHub stars as of Nov 1, 2026. It gained 156 new stars in the week of Oct 25–31, 2026, against a 12-week average of 153 a week. Its main package had about 4.6M downloads that week, +45% against its own 4-week average. That made it #4 among AI agent frameworks on the Devtoolwatch Board.

### What are the best alternatives to AG-UI?

Other AI agent frameworks on the Devtoolwatch Board in the week of Oct 25–31, 2026, by momentum: Harness² (#1), HyperFrames (#2), AgentScope (#3), LangGraph (#5), Bifrost (#6). The alternatives table above has their numbers.

### What is the difference between AG-UI and A2UI?

AG-UI is the agent-user interaction protocol that connects an agentic frontend to any agentic backend. A2UI is a generative UI specification that lets agents deliver UI widgets. The AG-UI docs say the two are different and work well together.

### How does AG-UI relate to A2A and MCP?

AG-UI is complementary to both. MCP gives agents tools and data. A2A lets agents communicate with other agents. AG-UI brings agents into user-facing applications. AG-UI also lists A2A as a supported agent interaction protocol.

### Does AG-UI support MCP Apps?

Yes. AG-UI lists MCP Apps as a supported generative UI integration, with documentation available.

### What transports does AG-UI work with?

AG-UI works with any event transport, including SSE, WebSockets and webhooks. It also ships a reference HTTP implementation and a default connector.

### Is AG-UI tied to CopilotKit?

AG-UI grew out of CopilotKit's partnership with LangChain and CrewAI. CopilotKit is a first-party client, but other clients are also supported, including terminal apps, Slack, Microsoft Teams and React Native.

## Sources

1. [ag-ui-protocol/ag-ui on GitHub](https://github.com/ag-ui-protocol/ag-ui)
2. [AG-UI README](https://github.com/ag-ui-protocol/ag-ui/blob/main/README.md)
3. [@ag-ui/core on npm](https://www.npmjs.com/package/@ag-ui/core)
4. [AG-UI website](https://ag-ui.com)
5. [Release release/2026-10-21 (Oct 21, 2026)](https://github.com/ag-ui-protocol/ag-ui/releases/tag/release/2026-10-21)
6. [Release release/2026-10-19 (Oct 19, 2026)](https://github.com/ag-ui-protocol/ag-ui/releases/tag/release/2026-10-19)
7. [Release release/2026-10-18 (Oct 18, 2026)](https://github.com/ag-ui-protocol/ag-ui/releases/tag/release/2026-10-18)
8. [Hacker News: Show HN: AG-UI Protocol – Bring Agents into Frontend Applications](https://news.ycombinator.com/item?id=43974484)
9. [Devtoolwatch Board, the week of Oct 25–31, 2026](https://index.devtoolwatch.com/)