TanStack Query is a library that helps you manage server data in React apps. It makes handling API requests and async data much easier. Originally called React Query, it now works with other frameworks like Vue, Solid, and Svelte too.
According to the official documentation: "TanStack Query (FKA React Query) is often described as the missing data-fetching library for web applications, but in more technical terms, it makes fetching, caching, synchronizing and updating server state in your web applications a breeze."
Why choose TanStack Query?
There are several compelling reasons why developers prefer TanStack Query over other data fetching solutions. Let's explore the key benefits that make it stand out.
1. Simplified server state management
Most state managers like Redux or MobX are built for client-side state. TanStack Query focuses specifically on server data. You don't need to manually handle caching, syncing, or error states anymore.
2. Smart caching
The library automatically caches your data and only updates when needed. If you make the same API call multiple times, it'll use the cached version instead of making unnecessary requests.
3. Automatic data updates
TanStack Query keeps your data fresh with features like refetching and background sync. When users switch back to your tab or navigate between pages, it automatically refreshes the data behind the scenes.
4. Server-side rendering (SSR) support
If you're using Next.js or similar frameworks, TanStack Query helps you preload data on the server. This improves both SEO and page loading speed.
5. Intuitive API
The API is declarative and straightforward. Your code becomes cleaner and easier to maintain.
Comparing TanStack Query with other libraries
TanStack Query stands out from libraries like SWR or Axios because it comes with more built-in features. You get cache management, optimistic updates, and automatic synchronization right out of the box.
Does TanStack Query replace Redux, MobX or other global state managers?
Here's what the TanStack team says (the answer is - it can replace them or work alongside them):
TanStack Query is a server-state library, responsible for managing asynchronous operations between your server and client.
Redux, MobX, Zustand, etc. are client-state libraries that can be used to store asynchronous data, albeit inefficiently when compared to a tool like TanStack Query.
There are still some circumstances where an application might indeed have a massive amount of synchronous client-only state (like a visual designer or music production application), in which case, you will probably still want a client state manager. In this situation it's important to note that TanStack Query is not a replacement for local/client state management. However, you can use TanStack Query alongside most client state managers with zero issues.
Example: How to use TanStack Query
Let's walk through a simple example where we fetch a list of users from an API:
// api.js
export async function fetchUsers() {
const response = await fetch('https://jsonplaceholder.typicode.com/users');
if (!response.ok) {
throw new Error('Network response was not ok');
}
return response.json();
}
1. Installation
Install the library using npm or Yarn:
npm install @tanstack/react-query
2. Setting up QueryClient
// main.jsx
import React from 'react';
import ReactDOM from 'react-dom/client';
import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
import App from './App';
const queryClient = new QueryClient();
ReactDOM.createRoot(document.getElementById('root')).render(
<QueryClientProvider client={queryClient}>
<App />
</QueryClientProvider>
);
3. Fetching data with useQuery
// UsersList.jsx
import React from 'react';
import { useQuery } from '@tanstack/react-query';
import { fetchUsers } from './api';
function UsersList() {
const { data, error, isLoading } = useQuery(['users'], fetchUsers);
if (isLoading) return <p>Loading...</p>;
if (error) return <p>Error: {error.message}</p>;
return (
<ul>
{data.map(user => (
<li key={user.id}>{user.name}</li>
))}
</ul>
);
}
export default UsersList;
4. Automatic updates
TanStack Query can automatically refresh data when users switch back to your browser tab:
useQuery(['users'], fetchUsers, {
refetchOnWindowFocus: true, // Refresh data when tab is refocused
});
5. Mutations for data modification
When you need to send data to the server, use the useMutation hook:
import { useMutation, useQueryClient } from '@tanstack/react-query';
function AddUser() {
const queryClient = useQueryClient();
const mutation = useMutation(newUser => fetch('/api/users', {
method: 'POST',
body: JSON.stringify(newUser),
}), {
onSuccess: () => {
// Refresh the cache after adding a new user
queryClient.invalidateQueries(['users']);
},
});
const handleAddUser = () => {
mutation.mutate({ name: 'John Doe' });
};
return (
<button onClick={handleAddUser} disabled={mutation.isLoading}>
Add User
</button>
);
}
Debugging and DevTools
TanStack Query comes with excellent debugging tools that make it easy to see what's happening with your queries and mutations:
1. Installing the DevTools
You can install a separate package for the debugging interface:
npm install @tanstack/react-query-devtools
2. Adding DevTools to your application
Add the DevTools component to see what's happening inside your app:
import { ReactQueryDevtools } from '@tanstack/react-query-devtools';
function App() {
return (
<>
{/* Your application components */}
<ReactQueryDevtools initialIsOpen={false} />
</>
);
}
3. Key features of DevTools
Active queries panel: See all your running queries, their status (loading, error, success), and cached data
Refetch button: Manually trigger queries again for testing
Detailed query information: Check query keys, fetch status, and timing info
4. Debugging tips
Network failures: Use DevTools to figure out if errors come from your server or client code
Cache issues: Check cached data to make sure queries update when they should
Mutation tracking: Watch your data updates as they happen
Conclusion
TanStack Query makes handling server data much simpler. It takes care of caching, refetching, and keeping your data in sync automatically. With features like smart caching, background updates, and great TypeScript support, it's become essential for modern React applications. Whether you're building a small project or a large-scale app, TanStack Query will save you time and make your code more reliable.
