Quick Start: Vue | TanStack AI Docs

You have a Vue 3 app and want to add AI chat. By the end of this guide, you'll have a streaming chat component powered by TanStack AI and OpenAI.

Tip: If you'd prefer not to sign up with individual AI providers, OpenRouter gives you access to 300+ models with a single API key and is the easiest way to get started.

Installation

npm install @tanstack/ai @tanstack/ai-vue @tanstack/ai-openai
# or
pnpm add @tanstack/ai @tanstack/ai-vue @tanstack/ai-openai
# or
yarn add @tanstack/ai @tanstack/ai-vue @tanstack/ai-openai

Server Setup

Vue apps typically use a separate backend. Here's an Express server that streams chat responses:

typescript

import express from 'express'
import { chat, toServerSentEventsResponse } from '@tanstack/ai'
import { openaiText } from '@tanstack/ai-openai'

const app = express()
app.use(express.json())

app.post('/api/chat', async (req, res) => {
  const { messages, conversationId } = req.body

  if (!process.env.OPENAI_API_KEY) {
    res.status(500).json({ error: 'OPENAI_API_KEY not configured' })
    return
  }

  try {
    const stream = chat({
      adapter: openaiText('gpt-4o'),
      messages,
      conversationId,
    })

    const response = toServerSentEventsResponse(stream)
    res.writeHead(response.status, Object.fromEntries(response.headers))

    const body = response.body
    if (body) {
      const reader = body.getReader()
      const pump = async () => {
        const { done, value } = await reader.read()
        if (done) {
          res.end()
          return
        }
        res.write(value)
        await pump()
      }
      await pump()
    }
  } catch (error) {
    res.status(500).json({
      error: error instanceof Error ? error.message : 'An error occurred',
    })
  }
})

app.listen(3000, () => console.log('Server running on port 3000'))

Tip: Any backend that returns the TanStack AI SSE format works -- you can use Fastify, Hono, Nitro, or any other Node.js framework.

Client Setup

Create a Chat.vue component using the useChat composable:

vue

<script setup lang="ts">
import { ref } from 'vue'
import { useChat, fetchServerSentEvents } from '@tanstack/ai-vue'

const input = ref('')

const { messages, sendMessage, isLoading } = useChat({
  connection: fetchServerSentEvents('/api/chat'),
})

function handleSubmit() {
  if (input.value.trim() && !isLoading.value) {
    sendMessage(input.value)
    input.value = ''
  }
}
</script>

<template>
  <div class="chat">
    <div class="messages">
      <div
        v-for="message in messages.value"
        :key="message.id"
        :class="message.role"
      >
        <strong>{{ message.role === 'assistant' ? 'Assistant' : 'You' }}</strong>
        <div v-for="(part, idx) in message.parts" :key="idx">
          <p v-if="part.type === 'text'">{{ part.content }}</p>
        </div>
      </div>
    </div>

    <form @submit.prevent="handleSubmit">
      <input
        v-model="input"
        placeholder="Type a message..."
        :disabled="isLoading.value"
      />
      <button type="submit" :disabled="!input.trim() || isLoading.value">
        Send
      </button>
    </form>
  </div>
</template>

Environment Variables

Create a .env file (or .env.local depending on your setup) with your API key:

# OpenRouter (recommended — access 300+ models with one key)
OPENROUTER_API_KEY=sk-or-...

# OpenAI
OPENAI_API_KEY=your-openai-api-key

Your server reads this key at runtime. Never expose it to the browser.

Vue-Specific Notes

Reactive state uses ShallowRef. The useChat composable returns state wrapped in DeepReadonly<ShallowRef<>>. Access values with .value in both <script> and <template>:

vue

<script setup lang="ts">
// In script, use .value
if (isLoading.value) { /* ... */ }
const count = messages.value.length
</script>

<template>
  <!-- In template, also use .value (these are ShallowRefs, not regular refs) -->
  <span v-if="isLoading.value">Loading...</span>
  <span>{{ messages.value.length }} messages</span>
</template>

Automatic cleanup. The composable calls onScopeDispose internally, so in-flight requests are stopped when the component unmounts. No manual cleanup needed.

Same API shape as React. If you're coming from @tanstack/ai-react, the Vue composable returns the same properties (messages, sendMessage, isLoading, error, status, stop, reload, clear). The only difference is the ShallowRef wrapper.

That's It!

You now have a working Vue chat application. The useChat composable handles:

Message state management
Streaming responses
Loading states
Error handling

Next Steps

Learn about Tools to add function calling
Check out the Adapters to connect to different providers
See the React Quick Start if you're comparing frameworks