In Next.js, the built-in fetch API is your primary tool for retrieving data. It's a powerful and flexible way to interact with external APIs and data sources, whether you're running it on the server or the client. Next.js enhances the native fetch with automatic deduplication and caching, making your data fetching more efficient and performant.
The core concept is straightforward: you use fetch just like you would in a standard browser environment, but Next.js adds intelligent caching layers behind the scenes.
async function getData() {
const res = await fetch('https://api.example.com/data');
if (!res.ok) {
throw new Error('Failed to fetch data');
}
return res.json();
}When you use fetch within Server Components, Next.js provides automatic request deduplication. This means if you call fetch multiple times with the same URL within a single render pass, Next.js will only execute the request once, significantly reducing redundant network calls and improving performance.
graph TD;
A[Component Rendering] --> B{Multiple fetch calls to same URL?};
B -- Yes --> C[Next.js Deduplication];
C --> D[Single Network Request];
B -- No --> D;
D --> E[Data Retrieved];
Next.js also leverages caching for fetch requests. By default, data fetched with fetch is cached on the server for the lifetime of the component. This means that subsequent renders of the same component, or even different components requesting the same data, will use the cached result instead of making a new network request.
You can control the caching behavior of fetch using options. For instance, cache: 'no-store' will prevent caching and always fetch fresh data, which is useful for dynamic or frequently changing information. Conversely, cache: 'force-cache' (the default) ensures data is cached.
async function getLiveStockData() {
const res = await fetch('https://api.example.com/stocks/live', {
cache: 'no-store'
});
if (!res.ok) {
throw new Error('Failed to fetch live stock data');
}
return res.json();
}Another important option is next.revalidate. This option allows you to specify a time in seconds after which a cached response will be considered stale and a new request will be made on the next access. This provides a balance between the performance benefits of caching and the need for relatively up-to-date data.
async function getLatestArticles() {
const res = await fetch('https://api.example.com/articles/latest', {
next: { revalidate: 60 } // Revalidate every 60 seconds
});
if (!res.ok) {
throw new Error('Failed to fetch latest articles');
}
return res.json();
}Understanding these options for fetch within your Next.js applications is crucial for building performant and efficient data-driven user experiences. Experiment with these settings to find the optimal balance for your specific data fetching needs.