Data Fetching Basics

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Data fetching is a core feature of Next.js that allows you to load data from APIs, databases, or external services efficiently. Next.js provides different data-fetching methods depending on where and how the data is needed.

1. Data Fetching in the App Router

In the App Router (app/ directory), data fetching is handled primarily using the fetch() API.
By default, data is fetched on the server, making applications faster and SEO-friendly.

2. Server-Side Data Fetching

Basic Example

async function getData() {
  const res = await fetch('https://api.example.com/posts');
  return res.json();
}

export default async function Page() {
  const data = await getData();

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

• Runs on the server

• Data is not exposed to the browser

• Ideal for SEO and secure data

3. Static Data Fetching (SSG)

By default, fetch() uses static rendering.

await fetch('https://api.example.com/posts');

• Data is fetched at build time

• Best for blogs, landing pages, and static content

• Very fast performance

4. Dynamic Data Fetching

To fetch fresh data on every request, use:

await fetch('https://api.example.com/posts', {
  cache: 'no-store',
});

• Data is fetched on each request

• Suitable for dashboards and real-time data

5. Revalidation (ISR)

You can revalidate data after a specific time.

await fetch('https://api.example.com/posts', {
  next: { revalidate: 60 },
});

• Data refreshes every 60 seconds

• Combines speed and freshness

6. Client-Side Data Fetching

For interactive or user-driven data, fetch data on the client.

'use client';

import { useEffect, useState } from 'react';

export default function ClientData() {
  const [data, setData] = useState([]);

  useEffect(() => {
    fetch('/api/posts')
      .then(res => res.json())
      .then(setData);
  }, []);

  return <div>{data.length} Posts</div>;
}

7. When to Use Which Method

Conclusion

Next.js data fetching is flexible and optimized by default. By choosing the right fetching strategy—static, dynamic, or client-side—you can build fast, scalable, and SEO-friendly applications.