Usage with Next.js

Client Side Data Fetching#

If your page contains frequently updating data, and you don’t need to pre-render the data, SWR is a perfect fit and no special setup needed: just import useSWR and use the hook inside any components that use the data.

Here’s how it works:

• First, immediately show the page without data. You can show loading states for missing data.
• Then, fetch the data on the client side and display it when ready.

This approach works well for user dashboard pages, for example. Because a dashboard is a private, user-specific page, SEO is not relevant and the page doesn’t need to be pre-rendered. The data is frequently updated, which requires request-time data fetching.

Pre-rendering with Default Data#

If the page must be pre-rendered, Next.js supports 2 forms of pre-rendering:
Static Generation (SSG) and Server-side Rendering (SSR).

Together with SWR, you can pre-render the page for SEO, and also have features such as caching, revalidation, focus tracking, refetching on interval on the client side.

You can use the fallback option of SWRConfig to pass the pre-fetched data as the initial value of all SWR hooks. For example with getStaticProps:

export async function getStaticProps () {
  // `getStaticProps` is executed on the server side.
  const article = await getArticleFromAPI()
  return {
    props: {
      fallback: {
        '/api/article': article
      }
    }
  }
}

function Article() {
  // `data` will always be available as it's in `fallback`.
  const { data } = useSWR('/api/article', fetcher)
  return <h1>{data.title}</h1>
}

export default function Page({ fallback }) {
  // SWR hooks inside the `SWRConfig` boundary will use those values.
  return (
    <SWRConfig value={{ fallback }}>
      <Article />
    </SWRConfig>
  )
}

The page is still pre-rendered. It's SEO friendly, fast to response, but also fully powered by SWR on the client side. The data can be dynamic and self-updated over time.