People searching for an "agent chat UI" usually want one of two things. Some want an app they can deploy today to chat with models and agents. Others want a frontend library to put a chat interface in front of an agent they've built themselves. The table covers both, using projects that AI Rank tracks in its Build agent UI and Personal app categories.
The ranking
| # | Project | Type | GitHub stars | 7-day change | License |
|---|---|---|---|---|---|
| 1 | Open WebUI | Self-hosted app | 155,784 | +1,570 | Open WebUI License |
| 2 | LobeHub | Self-hosted app | 83,244 | +184 | LobeHub Community License |
| 3 | LibreChat | Self-hosted app | 45,737 | +338 | MIT |
| 4 | CopilotKit | Frontend framework | 38,031 | +197 | MIT |
| 5 | assistant-ui | React library | 12,559 | +116 | MIT |
| 6 | Hugging Face Chat UI | Self-hosted app | 10,985 | +11 | Apache-2.0 |
| 7 | LangChain Agent Chat UI | Next.js app for LangGraph | 3,218 | +15 | MIT |
| 8 | Agno Agent UI | Next.js app for Agno | 1,857 | 0 | MIT |
The ranking is by total GitHub stars from the AI Rank repositories API, snapshot October 16, 2026. The 7-day change is the net star gain over the previous week. Licenses come from each repository. Stars measure developer attention, not quality.
Self-hosted chat apps
Open WebUI: the default pick
Open WebUI is the largest and fastest-growing project here, with 1,570 new stars this week. Its README describes a self-hosted AI platform that you install with pip, uv, Docker or Kubernetes. It connects to any OpenAI-compatible API as well as local Ollama models. You can build agents by wrapping a model with instructions, tools and knowledge, then extend them through MCP, MCPO and OpenAPI tool servers. One thing to check: its license is the custom Open WebUI License, not a standard OSI license, so read it before you rebrand or resell.
LobeHub
LobeHub describes itself as organizing "your agents into 7×24 operation", and you can self-host it with Docker. It uses the LobeHub Community License, so check the terms for commercial use.
LibreChat: MIT-licensed and built around agents
LibreChat bills itself as an "Enhanced ChatGPT Clone" with agents, MCP and skills. Its README lists an Agent Management API (beta), a trace viewer for tool rounds and costs, and OpenTelemetry log export. If you need a self-hosted app under a standard MIT license, this is the strongest option on the list.
Hugging Face Chat UI
Chat UI is the codebase behind HuggingChat. Its README says it now speaks to OpenAI-compatible APIs only, and it needs MongoDB. It suits simple chat over an inference endpoint more than complex agents. It gained just 11 stars this week.
Frameworks for your own agent
CopilotKit
CopilotKit calls itself "the frontend stack for agents & generative UI". It covers generative UI, shared state and human-in-the-loop workflows for React, Angular, Vue and React Native, plus Slack and Microsoft Teams. The CopilotKit team created the AG-UI protocol, which its README says has been adopted by LangChain, Google, AWS, Microsoft, Mastra and others.
assistant-ui
assistant-ui is a TypeScript/React library for building "production-grade AI chat experiences". It connects to the Vercel AI SDK out of the box and includes a useLangGraphRuntime adapter for LangGraph backends. It also supports generative UI, so tool calls can render as React components with inline approvals.
LangChain chat UI options
For a LangChain chat UI, there are three main options:
| Option | What it is | Choose it when |
|---|---|---|
| LangChain Agent Chat UI | Official Next.js app from LangChain | You have a LangGraph server and want a working chat UI in minutes |
assistant-ui + useLangGraphRuntime |
React library | You want the chat inside your own product's UI |
| CopilotKit (AG-UI) | Agent frontend framework | You need generative UI or shared state between agent and app |
According to its README, Agent Chat UI lets you chat with "any LangGraph server with a messages key". You can start it with npx create-agent-chat-app, then enter three values: a deployment URL, an assistant or graph ID, and a LangSmith API key (needed only for deployed servers). It has the fewest stars of the eight (3,218, +15 this week), but it's the only one built by LangChain specifically for LangGraph.
Agno Agent UI is the same idea for the Agno framework. It shows tool calls, reasoning steps and references. GitHub shows its last push on May 8, 2026.
How to choose
| You want... | Pick |
|---|---|
| A ChatGPT-style app for your team, with local models | Open WebUI |
| A self-hosted agent app under the MIT license | LibreChat |
| A chat UI for an existing LangGraph agent | LangChain Agent Chat UI |
| A chat component inside your own React app | assistant-ui |
| Generative UI and agent/app shared state across web, mobile and Slack | CopilotKit |
FAQ
What is the best open source agent chat UI? By AI Rank's data, Open WebUI leads on both total stars (155,784) and weekly growth (+1,570). If license terms matter, LibreChat is the largest MIT-licensed app on the list.
Does LangChain have an official chat UI?
Yes. langchain-ai/agent-chat-ui is a Next.js app that connects to any LangGraph server with a messages key.
Which agent chat UI works with MCP? Open WebUI and LibreChat both list MCP support in their READMEs.
Sources
- AI Rank: Repositories API and repo pages linked above (snapshot Oct 16, 2026)
- GitHub: open-webui/open-webui, lobehub/lobehub, LibreChat-AI/LibreChat, CopilotKit/CopilotKit, assistant-ui/assistant-ui, huggingface/chat-ui, langchain-ai/agent-chat-ui, agno-agi/agent-ui
Keep exploring: track these agent chat UIs day by day in the open-source rankings on AI Rank.
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Prepared with automated editorial assistance and checked against official sources and dated AI Rank data on October 16, 2026. We did not run our own benchmarks for this article.