TanStack
AI
UI

Solid Chat UI

createChatHook from @tanstack/ai-solid/ui binds your chat options and components once. Tool calls and approvals stay typed.

Each screen then renders the chat with one hook call. You supply every visible component. There is no default markup or style.

Note

Upgrading from @tanstack/ai-solid-ui? Read Upgrade to 1.0.

Quick setup

  1. Install the packages:
shell
npm i @tanstack/ai @tanstack/ai-solid @tanstack/ai-openai
  1. Put OPENAI_API_KEY in your server environment. Then add a POST route at /api/chat:
ts
import {
  chat,
  chatParamsFromRequest,
  toServerSentEventsResponse,
} from '@tanstack/ai'
import { openaiText } from '@tanstack/ai-openai'

export async function POST(request: Request) {
  const { messages, threadId, runId } = await chatParamsFromRequest(request)

  const stream = chat({
    adapter: openaiText('gpt-6.1-sol'),
    messages,
    threadId,
    runId,
  })

  return toServerSentEventsResponse(stream)
}
  1. Create src/chat.tsx:
tsx
import { fetchServerSentEvents } from '@tanstack/ai-solid'
import { createChatHook } from '@tanstack/ai-solid/ui'

const chatOptions = {
  connection: fetchServerSentEvents('/api/chat'),
}

const { useAppChat } = createChatHook({
  options: chatOptions,
  components: {
    layout: (props) => (
      <section>
        <props.Messages />
      </section>
    ),
    message: (props) => (
      <article data-role={props.message.role}>
        <props.Parts />
      </article>
    ),
  },
  partsComponents: {
    text: (props) => <p>{props.part.content}</p>,
    fallback: () => null,
  },
})

export function ChatScreen() {
  const chat = useAppChat({ threadId: 'support-chat' })

  return (
    <main>
      <chat.AppChat />
      <form
        onSubmit={(event) => {
          event.preventDefault()
          const field = event.currentTarget.elements.namedItem('message')
          if (!(field instanceof HTMLInputElement)) return
          const text = field.value.trim()
          if (!text) return
          field.value = ''
          void chat.sendMessage(text)
        }}
      >
        <input name="message" />
        <button type="submit">Send</button>
      </form>
    </main>
  )
}
  1. Render <ChatScreen /> and send a message.

The reply streams into the page as the model writes it.

How it works

  • createChatHook runs once, at module scope. It binds chatOptions to your components.
  • useAppChat({ threadId }) creates one chat instance. chat.AppChat renders that instance with your components.
  • layout places the message list. message wraps one message. Parts picks a component for each part of that message.
  • partsComponents.text renders text. fallback catches every part type that you did not register.

Read props as props.part and props.Messages. Do not destructure them, or Solid stops tracking the values.

Next steps

Each step adds one thing to the quick setup. The chat UI recipes have the full file for each one. The recipes use React, and the option names are the same in Solid.

Render a tool

Add the tool to tools in chatOptions. Then register a component under the tool name in toolsComponents. part.input and part.output are typed from the tool schemas.

tsx
toolsComponents: {
  getWeather: (props) =>
    props.part.state === 'complete' ? (
      <p>
        {props.part.input?.city}: {props.part.output?.temperature}
      </p>
    ) : (
      <p>Looking up weather</p>
    ),
},

The factory needs one entry for every tool in chatOptions. Full example: Make a tool look right.

Ask before a tool runs

Set needsApproval: true on the tool. The tool component then gets an interrupt prop:

tsx
toolsComponents: {
  deleteFile: (props) =>
    props.interrupt?.status === 'pending' ? (
      <button onClick={() => props.interrupt?.resolveInterrupt(true)}>
        Delete {props.part.input?.path}
      </button>
    ) : (
      <p>{props.part.input?.path}</p>
    ),
},

resolveInterrupt(true) approves. resolveInterrupt(false) denies. Full example: Ask before a tool runs.

Ask the user your own question

Define the question with defineInterrupt. Add it to interrupts in chatOptions. Register a component under its id in interruptsComponents.generic, and render props.Interrupts in the layout:

tsx
const choosePlan = defineInterrupt({
  id: 'choosePlan',
  payloadSchema: z.object({ title: z.string() }),
  responseSchema: z.string(),
})

// In createChatHook:
interruptsComponents: {
  generic: {
    choosePlan: (props) => (
      <button onClick={() => props.interrupt.resolveInterrupt('pro')}>
        {props.interrupt.payload?.title}
      </button>
    ),
    fallback: (props) => <p>{props.interrupt.reason}</p>,
  },
},

The factory needs one entry for every interrupt id in chatOptions. Full example: Ask the user your own question.

Read chat state inside a widget

Mapped components do not get chat as a prop. Call useChatContext() inside the widget. This also moves the composer into the layout: register it as input, then render props.Input.

tsx
import { createSignal } from 'solid-js'
import { fetchServerSentEvents } from '@tanstack/ai-solid'
import { createChatHook } from '@tanstack/ai-solid/ui'

const chatOptions = {
  connection: fetchServerSentEvents('/api/chat'),
}

const { useAppChat, useChatContext } = createChatHook({
  options: chatOptions,
  components: {
    input: () => {
      const chat = useChatContext()
      const [draft, setDraft] = createSignal('')
      return (
        <form
          onSubmit={(event) => {
            event.preventDefault()
            void chat.sendMessage(draft())
            setDraft('')
          }}
        >
          <input
            value={draft()}
            disabled={chat.isLoading()}
            onInput={(event) => setDraft(event.currentTarget.value)}
          />
          <button type="submit">Send</button>
        </form>
      )
    },
    layout: (props) => (
      <main>
        <props.Messages />
        <props.Input />
      </main>
    ),
    message: (props) => (
      <article>
        <props.Parts />
      </article>
    ),
  },
  partsComponents: {
    text: (props) => <p>{props.part.content}</p>,
    fallback: () => null,
  },
})

export function ChatScreen() {
  const chat = useAppChat({ threadId: 'support-chat' })
  return <chat.AppChat />
}

In Solid, chat.messages, chat.isLoading, and chat.error are accessors. Call them, such as chat.messages().length. Call useChatContext() only inside chat.AppChat. A call outside that tree throws.

Render markdown

Model replies arrive as markdown. Register TextPart from @tanstack/ai-solid/ui as the text part:

tsx
import { TextPart } from '@tanstack/ai-solid/ui'

partsComponents: {
  text: (props) => <TextPart content={props.part.content} />,
  fallback: () => null,
},

TextPart uses TanStack Markdown. It escapes raw HTML and removes executable URLs. To color fenced code, read Highlight markdown code.

Type a widget in its own file

Move a widget to its own file and type its props with ToolProps, PartProps, or InterruptProps. Pass typeof chatOptions and a name. Keep the props object so Solid can track it:

tsx
import { fetchServerSentEvents } from '@tanstack/ai-solid'
import { createChatHook, type ToolProps } from '@tanstack/ai-solid/ui'
import { toolDefinition } from '@tanstack/ai'
import { z } from 'zod'

const getWeather = toolDefinition({
  name: 'getWeather',
  description: 'Look up weather',
  inputSchema: z.object({ city: z.string() }),
  outputSchema: z.object({ temperature: z.number() }),
}).client()

const chatOptions = {
  connection: fetchServerSentEvents('/api/chat'),
  tools: [getWeather],
}

export function WeatherTool(
  props: ToolProps<typeof chatOptions, 'getWeather'>,
) {
  return <strong>{props.part.input?.city}</strong>
}

export const { useAppChat } = createChatHook({
  options: chatOptions,
  components: {
    layout: (props) => <props.Messages />,
    message: (props) => (
      <article>
        <props.Parts />
      </article>
    ),
  },
  partsComponents: { fallback: () => null },
  toolsComponents: { getWeather: WeatherTool },
})

Put chatOptions in a shared module so every widget file can import its type.

You now have a typed chat UI in Solid. Each widget is your own component.

Advanced

Slots and props

The config keys, part keys, and prop types are the same as in React. See Every widget slot. In Solid, layout gets Messages, Interrupts, and Queue, plus Input when you register input.

useAppChat() takes per-instance options: threadId (required), initialMessages, live, and forwardedProps.

Approvals and generic interrupts

  • A tool approval renders in the tool when you read props.interrupt.
  • To show it in the list instead, register a component under interruptsComponents.tools and render props.Interrupts.
  • Generic interrupts always render in the list. generic.fallback renders an unregistered id and an unbound interrupt. If the copy must be different, branch on interrupt.kind === 'unbound'.

List input before layout

If input is an inline function expression written after layout, TypeScript cannot see that an input is registered. Then Input is missing from the layout props.

To prevent this, put input first, or use an arrow function or a named component. If it still slips through, <props.Input /> without a registered input warns once in development.

Widgets in other files

Call createChatHookContexts() in its own module. Pass chatContext, partContext, and interruptContext to createChatHook under context. Widget files then import useChatContext from the contexts module, with no circular import.

Walk messages yourself

createChatUI is the lower-level kit. The UI.Messages render callback gets an accessor:

tsx
<UI.Messages>{(messages) => <span>{messages().length}</span>}</UI.Messages>

TextPart options

  • highlighter: a synchronous CodeHighlighter. Its output is trusted HTML, so use createTanStackMarkdownHighlighter or another highlighter that escapes source text.
  • extensions: more TanStack Markdown extensions. The streaming extension is always on.
  • class, userClass, assistantClass: classes for the wrapper. Pass role to apply the role class.

If you still pass remarkPlugins, rehypePlugins, disableDefaultPlugins, or components, read TextPart markdown.

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