Mastering React Query in 2025: A Deep Dive into Data Fetching for Modern Apps

When building modern React applications, data fetching is no longer just about hitting an API — it’s about caching, synchronization, background updates, offline support, and delivering a seamless UX even under poor network conditions.

In 2025, React Query (now part of TanStack Query) remains the go-to library for managing server state, with a mature API, strong community, and deep integration with modern React features like Suspense, concurrent rendering, and server components.

This guide takes you beyond the basics into enterprise-grade patterns, real-world optimizations, and future-facing features.

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Why React Query?

React Query eliminates much of the boilerplate traditionally associated with data fetching by providing:

• Smart Caching — Cache results and re-use them without redundant network calls.
• Automatic Background Updates — Keep data fresh without manual refetch logic.
• Out-of-the-Box Pagination & Infinite Loading — Easily implement common UI patterns.
• Offline & Network Recovery — Queue mutations and retry on reconnect.
• Devtools Integration — Inspect queries, cache, and performance in real-time.

Related: Official React Query Documentation

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Core Concepts

Queries

A query is any async function whose result you want to cache and manage.

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

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

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

  return <ul>{data.map(todo => <li key={todo.id}>{todo.title}</li>)}</ul>;
}

Related: Queries in React Query

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Mutations

Mutations handle creating, updating, or deleting data on the server.

import { useMutation, useQueryClient } from '@tanstack/react-query';

function AddTodo() {
  const queryClient = useQueryClient();
  const mutation = useMutation({
    mutationFn: (newTodo) => fetch('/api/todos', {
      method: 'POST',
      body: JSON.stringify(newTodo),
    }),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['todos'] });
    },
  });

  return (
    <button onClick={() => mutation.mutate({ title: 'New Task' })}>
      Add Todo
    </button>
  );
}

Related: Mutations in React Query

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Advanced Patterns

1. Prefetching & Initial Data

Prefetch queries before a user navigates to a page for instant load.

await queryClient.prefetchQuery({
  queryKey: ['projects'],
  queryFn: fetchProjects,
});

Related: Prefetching

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2. Infinite Queries for Endless Scrolling

React Query’s useInfiniteQuery simplifies infinite loading patterns.

const {
  data,
  fetchNextPage,
  hasNextPage,
  isFetchingNextPage,
} = useInfiniteQuery({
  queryKey: ['projects'],
  queryFn: fetchProjectsPaginated,
  getNextPageParam: (lastPage) => lastPage.nextCursor,
});

Related: Infinite Queries

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3. Optimistic Updates

Give users instant feedback by updating the UI before the server confirms.

const mutation = useMutation({
  mutationFn: updateTodo,
  onMutate: async (updatedTodo) => {
    await queryClient.cancelQueries({ queryKey: ['todos'] });
    const previousTodos = queryClient.getQueryData(['todos']);
    queryClient.setQueryData(['todos'], old =>
      old.map(todo => todo.id === updatedTodo.id ? updatedTodo : todo)
    );
    return { previousTodos };
  },
  onError: (err, updatedTodo, context) => {
    queryClient.setQueryData(['todos'], context.previousTodos);
  },
  onSettled: () => {
    queryClient.invalidateQueries({ queryKey: ['todos'] });
  },
});

Related: Optimistic Updates

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4. Offline Support

With React Query’s integration with localforage, you can persist cache and enable offline-ready experiences.

import { persistQueryClient } from '@tanstack/react-query-persist-client';
import { createSyncStoragePersister } from '@tanstack/query-sync-storage-persister';

const localStoragePersister = createSyncStoragePersister({ storage: window.localStorage });

persistQueryClient({
  queryClient,
  persister: localStoragePersister,
});

Related: Persisting Queries

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Performance Considerations

1. Cache Time vs Stale Time — Tune to balance freshness and performance.
2. Batching & Window Focus — Disable refetch on window focus if unnecessary.
3. Server-Side Rendering (SSR) — Prefetch data server-side and hydrate on the client.
4. Devtools in Production? — Only enable in staging/dev environments.

Related: Performance Optimizations

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React Query in the Context of RSC and Concurrent Features

With React 18 and beyond:

• Suspense for Data Fetching pairs perfectly with React Query for declarative loading states.
• Concurrent Rendering benefits from React Query’s ability to pause and resume work seamlessly.
• React Server Components (RSC) can integrate with React Query for hybrid data-fetching strategies.

Related: Using React Query with Suspense

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Key Takeaways

• React Query abstracts server-state management, enabling fast, reliable, and maintainable data flows.
• Prefetching, infinite queries, optimistic updates, and offline support are production-grade must-haves.
• Tuning cache/stale times and integrating with Suspense/RSC ensures your app is ready for the future of React.