Every AI product needs the same set of interface pieces, and they are harder to get right than they look. A conversation has to follow a streaming reply without fighting the reader who scrolls up. A prompt input needs attachments, a stop button and a queue. Tool calls need a status, an input, a result and sometimes an approval step. Markdown has to render while it's still arriving.
This guide compares the best React libraries for building AI chat UI in 2026: what each one ships, how it's styled, and which backends it works with.
- Create UI
- assistant-ui
- shadcn/ui AI Elements
- CopilotKit
- Ant Design X
- MUI X Chat
- Gravity UI AIKit
- coss ui Chat
What an AI chat UI needs
Quick comparison
1. Create UI: AI chat components inside a full design system
🔗 createui.co
Our own pick. Create UI includes a complete set of AI chat components, part of the same React and Tailwind CSS v4 design system as its 80+ components and 73 blocks:
- Chat Conversation follows streamed replies and stops when the reader scrolls up
- Chat Message and Chat Message Actions for turns, avatars, bubbles, copy, feedback and regenerate
- Prompt Input with attachments, run states, a follow-up queue and inline mentions
- Markdown that renders while text is still streaming in
- Chat Tool for tool calls with input, result, errors and approval
- Chain of Thought, Chat Source, Prompt Suggestion, Chat Attachment, Chat Loader, Chat List View and Text Shimmer
The components never own your messages, transport or streaming state, so they work with any backend. They accept Vercel AI SDK shapes directly, for example message.role for the message layout and the AI SDK tool part state for tool cards. Because they're part of the same system as the rest of the library, a chat screen matches your buttons, inputs and ready-made blocks without extra styling.
Pick it if: you want production-ready chat UI that looks like the rest of your product. The AI chat components are part of Create UI Pro.
2. assistant-ui: the most complete chat runtime
🔗 assistant-ui.com
assistant-ui is an MIT-licensed library of composable chat primitives with a shadcn-based theme on top. Its catalog is the widest of any chat-specific library, covering reasoning, sources, inline citations, tool fallbacks, follow-up suggestions and markdown. It connects to the AI SDK, LangGraph, LangChain and custom backends, and offers an optional paid Assistant Cloud.
Pick it if: chat is the core of your product and you want a dedicated runtime for it.
3. shadcn/ui AI Elements: the shadcn default
🔗 ui.shadcn.com
shadcn/ui added generic chat components in June 2026 and AI Elements in October 2026: about 21 copy-paste patterns including prompt input, reasoning, chain of thought, tools, confirmation, sources and suggestions. It replaces Vercel's AI SDK Elements, which will be deprecated at the end of November 2026, so start new projects on the shadcn version.
Pick it if: your app already runs on shadcn/ui.
4. CopilotKit: for apps driven by agents
🔗 copilotkit.ai
CopilotKit is less a chat kit and more an agent-to-UI framework. Built on the AG-UI protocol, it connects to LangGraph, Mastra, CrewAI, Google ADK, PydanticAI and other agent frameworks, and supports generative UI and human-in-the-loop flows. Its newer v2 components use Tailwind CSS v4. The library is MIT, with an optional paid cloud.
Pick it if: agents need to read and change your app's UI, not just chat in a sidebar.
5. Ant Design X: for Ant Design apps
🔗 x.ant.design
Ant Design X is a full AI interface kit: bubbles, a sender, attachments, streaming markdown, thought chains, sources, suggestions and conversation lists. It requires Ant Design 6 and uses its CSS-in-JS styling, so it fits best in apps already built on antd.
Pick it if: your product is built on Ant Design.
6. MUI X Chat: for Material UI apps
🔗 mui.com/x/react-chat
MUI X Chat provides a ChatBox with attachments, reasoning parts, tool calls with an approval flow, sources and suggestions, plus a headless package. It has a backend-agnostic adapter interface and a built-in AI SDK adapter. It's MIT licensed but still in early development, so expect API changes.
Pick it if: you're on Material UI and can live with an alpha.
7. Gravity UI AIKit: a lightweight, SDK-agnostic kit
🔗 github.com/gravity-ui/aikit
AIKit comes from Gravity UI, Yandex's design system. It offers a message list, prompt input, markdown renderer, thinking and tool messages, inline citations and suggestions, ships no LLM client, and is MIT licensed.
Pick it if: you use Gravity UI or want a small, backend-free kit.
8. coss ui Chat: for messaging-style chat
🔗 coss.com/ui/chat
coss ui's chat components are built for messaging apps: conversations, messages, reactions, replies and typing indicators, plus a composer that also works for AI assistants. It doesn't include AI-specific pieces like tool calls or reasoning.
Pick it if: you're building person-to-person chat on Tailwind and Base UI.
Older options to check carefully
Two once-popular libraries are worth a second look before you adopt them. chatscope chat-ui-kit-react hasn't shipped since May 2025 and has no AI-specific components. NLUX has had no release since August 2024 and only lists React 18 as a peer dependency. For a new AI product in 2026, the libraries above are safer bets.
How to choose
- Your chat screen should match the rest of your product: Create UI.
- Chat is the whole product: assistant-ui.
- You're already on shadcn/ui: shadcn/ui AI Elements.
- Agents need to drive the UI: CopilotKit.
- You're on Ant Design or Material UI: Ant Design X or MUI X Chat.
Looking at component libraries more broadly? See the best React UI component libraries and the best shadcn/ui alternatives.
