fetch
Next.js extends the Web fetch()
API to allow each request on the server to set its own persistent caching and revalidation semantics.
In the browser, the cache
option indicates how a fetch request will interact with the browser's HTTP cache. With this extension, cache
indicates how a server-side fetch request will interact with the framework's persistent Data Cache.
You can call fetch
with async
and await
directly within Server Components.
export default async function Page() {
let data = await fetch('https://api.vercel.app/blog')
let posts = await data.json()
return (
<ul>
{posts.map((post) => (
<li key={post.id}>{post.title}</li>
))}
</ul>
)
}
fetch(url, options)
Since Next.js extends the Web fetch()
API, you can use any of the native options available.
options.cache
Configure how the request should interact with Next.js Data Cache.
fetch(`https://...`, { cache: 'force-cache' | 'no-store' })
no-store
(default): Next.js fetches the resource from the remote server on every request without looking in the cache, and it will not update the cache with the downloaded resource.force-cache
: Next.js looks for a matching request in its Data Cache.- If there is a match and it is fresh, it will be returned from the cache.
- If there is no match or a stale match, Next.js will fetch the resource from the remote server and update the cache with the downloaded resource.
options.next.revalidate
fetch(`https://...`, { next: { revalidate: false | 0 | number } })
Set the cache lifetime of a resource (in seconds).
false
- Cache the resource indefinitely. Semantically equivalent torevalidate: Infinity
. The HTTP cache may evict older resources over time.0
- Prevent the resource from being cached.number
- (in seconds) Specify the resource should have a cache lifetime of at mostn
seconds.
Good to know:
- If an individual
fetch()
request sets arevalidate
number lower than the defaultrevalidate
of a route, the whole route revalidation interval will be decreased.- If two fetch requests with the same URL in the same route have different
revalidate
values, the lower value will be used.- As a convenience, it is not necessary to set the
cache
option ifrevalidate
is set to a number.- Conflicting options such as
{ revalidate: 3600, cache: 'no-store' }
will cause an error.
options.next.tags
fetch(`https://...`, { next: { tags: ['collection'] } })
Set the cache tags of a resource. Data can then be revalidated on-demand using revalidateTag
. The max length for a custom tag is 256 characters and the max tag items is 64.
Troubleshooting
Fetch cache: 'no-store'
not showing fresh data in development
Next.js caches fetch
responses in Server Components across Hot Module Replacement (HMR) in local development for faster responses and to reduce costs for billed API calls.
By default, the HMR cache applies to all fetch requests, including those with the cache: 'no-store'
option. This means uncached requests will not show fresh data between HMR refreshes. However, the cache will be cleared on navigation or full-page reloads.
See the serverComponentsHmrCache
docs for more information.
Version History
Version | Changes |
---|---|
v13.0.0 | fetch introduced. |
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