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AG-UI review

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

Updated Nov 1, 2026. Review written Oct 22, 2026 from the project's own sources; usage data refreshed every Monday.

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
Maintained by
ag-ui-protocol (organization, @ag-ui-protocol on GitHub)
License
MIT
Language
TypeScript, Python, C#
Repository
github.com/ag-ui-protocol/ag-ui
Website
ag-ui.com
npm package
@ag-ui/core 1.0.3
Latest release
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 and start using AG-UI

Create a new app with npx

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

Core package with npm

npm install @ag-ui/[email protected]

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 to know

  • 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.

Is AG-UI growing? Usage data

In the week of Oct 25–31, 2026, AG-UI ranked #64 on the Devtoolwatch Board and #4 in Agent frameworks, with a momentum score of 73 out of 100. Its main package had about 4.6M downloads that week, +45% against its own 4-week average.

New GitHub stars per week for AG-UI12 weeks from Aug 9, 2026: 142, 177, 135, 123, 125, 100, 110, 242, 155, 223, 149, 156 new stars, an average of 153 a week.Aug 9week of Oct 25
New GitHub stars per week for the last 12 weeks, from GitHub's stargazer history (today's stargazers by the week they starred).
Show the weekly numbers
New GitHub stars per week for AG-UI
Week ofNew stars
Aug 9, 2026142
Aug 16, 2026177
Aug 23, 2026135
Aug 30, 2026123
Sep 6, 2026125
Sep 13, 2026100
Sep 20, 2026110
Sep 27, 2026242
Oct 4, 2026155
Oct 11, 2026223
Oct 18, 2026149
Oct 25, 2026156

On Hacker News

The Board ranks tools by four signals each week: new stars, new stars for the repo's size, added downloads and download growth beyond the market. How the ranking works.

AG-UI alternatives

Other AI agent frameworks on the Board in the week of Oct 25–31, 2026, by momentum:

Agent frameworks ranked by momentum, the week of Oct 25–31, 2026
RankToolStarsDownloads/wk
#1Harness²Harness² is a Python framework from Google Research for recursive agent harnessing, refining an agent's prompts, tools, memory and…21.7k–
#2HyperFramesHyperFrames is an open-source framework that turns HTML, CSS, media, and seekable animations into deterministic MP4 videos, built for AI…76.6k1.5M
#3AgentScopeAgentScope is a Python agent framework with an SDK for building ReAct agents and an agent service backend with a web UI.35k51.4k
#5LangGraphLangGraph is a low-level orchestration framework and runtime for building, managing, and deploying long-running, stateful agents in…44.2k18.5M
#6BifrostOpen-source, high-performance AI gateway that works as your LLM gateway, MCP gateway and agent gateway. One OpenAI-compatible API for…9.3k–
#7assistant-uiassistant-ui is an open-source TypeScript/React library of composable primitives and runtimes for building AI chat interfaces in your app.12.9k2.8M

All AI agent frameworks, ranked

Recent AG-UI releases

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
  2. AG-UI README
  3. @ag-ui/core on npm
  4. AG-UI website
  5. Release release/2026-10-21 (Oct 21, 2026)
  6. Release release/2026-10-19 (Oct 19, 2026)
  7. Release release/2026-10-18 (Oct 18, 2026)
  8. Hacker News: Show HN: AG-UI Protocol – Bring Agents into Frontend Applications
  9. Devtoolwatch Board, the week of Oct 25–31, 2026

AG-UI README badge

Maintainers can show the tool's weekly Board rank in their README:

Devtoolwatch badge for AG-UI

[![Devtoolwatch](https://index.devtoolwatch.com/badge/ag-ui.svg)](https://index.devtoolwatch.com/tools/ag-ui/)

How this page is made: Devtoolwatch writes each review from the project's README, releases, package metadata and website, with an AI model, then checks every claim against the source it cites and drops what the sources don't support. The numbers come from Devtoolwatch's daily GitHub snapshots, GitHub's stargazer history, and the npm and PyPI download APIs. Spotted an error? Email [email protected].