bun add @pinia/colada pinia  # preferred

**For Nuxt Projects:**
```bash
bun add @pinia/nuxt @pinia/colada-nuxt  # install both Pinia and Pinia Colada modules

**Why this matters:**
- Pinia Colada requires Pinia 2.2.6+ or 3.0+ as peer dependency
- Nuxt module handles SSR serialization automatically
- Vue 3.5.17+ required for optimal reactivity

// src/main.ts
import { createApp } from 'vue'
import { createPinia } from 'pinia'
import { PiniaColada } from '@pinia/colada'
import App from './App.vue'

const app = createApp(App)
const pinia = createPinia()

app.use(pinia)
app.use(PiniaColada, {
  // Optional: Configure defaults
  query: {
    staleTime: 5000,        // 5 seconds
    gcTime: 5 * 60 * 1000,  // 5 minutes (garbage collection)
    refetchOnMount: true,
    refetchOnWindowFocus: false,
  },
})

app.mount('#app')

// nuxt.config.ts
export default defineNuxtConfig({
  modules: [
    '@pinia/nuxt',           // Must be before @pinia/colada-nuxt
    '@pinia/colada-nuxt',
  ],

  // Optional: Configure Pinia Colada
  piniaColada: {
    query: {
      staleTime: 5000,
      gcTime: 5 * 60 * 1000,
    },
  },
})

<script setup lang="ts">
import { useQuery } from '@pinia/colada'

interface Todo {
  id: number
  title: string
  completed: boolean
}

async function fetchTodos(): Promise<Todo[]> {
  const response = await fetch('/api/todos')
  if (!response.ok) {
    throw new Error('Failed to fetch todos')
  }
  return response.json()
}

const {
  data,       // Ref<Todo[] | undefined>
  isPending,  // Ref<boolean> - initial loading
  isLoading,  // Ref<boolean> - any loading (including refetch)
  error,      // Ref<Error | null>
  refresh,    // () => Promise<void> - manual refetch
} = useQuery({
  key: ['todos'],
  query: fetchTodos,
})
</script>

<template>
  <div>
    <div v-if="isPending">Loading todos...</div>
    <div v-else-if="error">Error: {{ error.message }}</div>
    <ul v-else-if="data">
      <li v-for="todo in data" :key="todo.id">
        {{ todo.title }}
      </li>
    </ul>
  </div>
</template>

<script setup lang="ts">
import { useMutation, useQueryCache } from '@pinia/colada'

interface NewTodo {
  title: string
}

async function createTodo(newTodo: NewTodo) {
  const response = await fetch('/api/todos', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(newTodo),
  })
  if (!response.ok) throw new Error('Failed to create todo')
  return response.json()
}

const queryCache = useQueryCache()

const {
  mutate,        // (variables: NewTodo) => Promise<void>
  mutateAsync,   // (variables: NewTodo) => Promise<Result>
  isPending,     // Ref<boolean>
  error,         // Ref<Error | null>
  data,          // Ref<Result | undefined>
} = useMutation({
  mutation: createTodo,

  // Invalidate todos query after mutation succeeds
  async onSettled({ id }) {
    await queryCache.invalidateQueries({ key: ['todos'] })
  },
})

function handleAddTodo(title: string) {
  mutate({ title })
}
</script>

<template>
  <form @submit.prevent="handleAddTodo(newTitle)">
    <input v-model="newTitle" required />
    <button type="submit" :disabled="isPending">
      {{ isPending ? 'Adding...' : 'Add Todo' }}
    </button>
    <div v-if="error">Error: {{ error.message }}</div>
  </form>
</template>

useMutation({
  mutation: createTodo,
  async onSettled() {
    await queryCache.invalidateQueries({ key: ['todos'] })
  },
})

onMutate(id) {
  cache.cancelQueries({ key: ['todos'] })
  // Then do optimistic update
}

useQuery({
  key: ['todos'],
  query: fetchTodos,
  refetchOnMount: false, // Prevents SSR hydration mismatch
})

// ❌ Wrong - static key
key: ['todos', id.value]

// ✅ Correct - reactive key
key: () => ['todos', id.value]

export default defineNuxtConfig({
  modules: [
    '@pinia/nuxt',           // MUST be first
    '@pinia/colada-nuxt',    // Then Colada
  ],
})

{
  "dependencies": {
    "@pinia/colada": "^0.17.9",
    "pinia": "^3.0.4",
    "vue": "^3.5.25"
  },
  "devDependencies": {
    "@pinia/colada-nuxt": "^0.17.9"
  }
}