What is TanStack Query?

TanStack Query (formerly React Query) is a powerful data-fetching library that simplifies server state management in React applications. Think of it as your smart assistant that handles all the complexity of fetching, caching, and synchronizing data from your backend.

Why Do You Need TanStack Query?

Without TanStack Query, managing server data in React can be painful. You often end up writing repetitive code for:

• Loading states
• Error handling
• Caching mechanisms
• Background refetching
• Optimistic updates

TanStack Query eliminates this complexity by providing a declarative approach to data fetching.

Key Features

• Smart Caching: Automatically caches your data and serves it instantly on subsequent requests
• Background Updates: Keeps your data fresh by refetching in the background
• Optimistic Updates: Updates UI immediately while syncing with server
• Error Recovery: Built-in retry logic and error boundaries
• DevTools: Excellent debugging experience with dedicated developer tools

Simple Example

import { useQuery } from '@tanstack/react-query'

function Profile() {
  const { data, isLoading, error } = useQuery({
    queryKey: ['profile'],
    queryFn: () => fetch('/api/profile').then(res => res.json())
  })

  if (isLoading) return <div>Loading...</div>
  if (error) return <div>Error: {error.message}</div>

  return <div>Hello {data.name}!</div>
}