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SWR


Introduction

SWR is a React Hooks library for data fetching.

The name “SWR” is derived from stale-while-revalidate, a cache invalidation strategy popularized by HTTP RFC 5861. SWR first returns the data from cache (stale), then sends the request (revalidate), and finally comes with the up-to-date data again.

With just one hook, you can significantly simplify the data fetching logic in your project. And it also covered in all aspects of speed, correctness, and stability to help you build better experiences:

  • Fast, lightweight and reusable data fetching
  • Transport and protocol agnostic
  • Built-in cache and request deduplication
  • Real-time experience
  • Revalidation on focus
  • Revalidation on network recovery
  • Polling
  • Pagination and scroll position recovery
  • SSR and SSG
  • Local mutation (Optimistic UI)
  • Built-in smart error retry
  • TypeScript
  • React Suspense
  • React Native

...and a lot more.

With SWR, components will get a stream of data updates constantly and automatically. Thus, the UI will be always fast and reactive.

View full documentation and examples on swr.vercel.app.


Quick Start

import useSWR from 'swr'

function Profile() {
  const { data, error, isLoading } = useSWR('/api/user', fetcher)

  if (error) return <div>failed to load</div>
  if (isLoading) return <div>loading...</div>
  return <div>hello {data.name}!</div&g