Server-Side Rendering vs. Static Site Generation in Next.js 14: When to Use Each

Next.js 14 with the App Router introduces a new paradigm for rendering strategies, simplifying the implementation of Server-Side Rendering (SSR) and Static Site Generation (SSG). In this comprehensive guide, we’ll explore the differences between SSR and SSG, their benefits, and when to use each approach in your Next.js 14 projects.

Understanding SSR and SSG in Next.js 14

In Next.js 14 with the App Router:

• Server-Side Rendering (SSR): Content is generated on the server for each request, now implemented using Server Components by default.
• Static Site Generation (SSG): Content is pre-rendered at build time, with options for static or dynamic rendering.

Server-Side Rendering (SSR) with App Router

In Next.js 14, SSR is the default behavior for Server Components. Here’s an example:

// app/ssr-example/page.tsx
async function getData() {
  const res = await fetch('https://api.example.com/data', { cache: 'no-store' })
  if (!res.ok) {
    throw new Error('Failed to fetch data')
  }
  return res.json()
}
export default async function SSRPage() {
  const data = await getData()
  return <div>{data.title}</div>
}

In this example, the getData function fetches fresh data on each request, ensuring the content is always up-to-date.

Static Site Generation (SSG) with App Router

For SSG in Next.js 14, you can use static rendering. Here’s how:

// app/ssg-example/page.tsx
export const revalidate = 3600 // revalidate every hour
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()
}
export default async function SSGPage() {
  const data = await getData()
  return <div>{data.title}</div>
}

This page will be statically generated at build time and revalidated every hour.

Comparing SSR and SSG

When to Use SSR

Use Server-Side Rendering when:

1. You need real-time data on every request
2. The content is highly personalized
3. You’re dealing with frequently changing data
4. SEO is crucial, and content updates often

Example use cases:

• Social media feeds
• E-commerce product pages with real-time inventory
• Personalized dashboards

When to Use SSG

Use Static Site Generation when:

1. The content doesn’t change frequently
2. You want the fastest possible initial load time
3. You’re building a large site with mostly static content
4. You want to reduce server load and costs

Example use cases:

• Blogs
• Marketing websites
• Documentation sites
• Portfolio websites

Hybrid Approaches and Dynamic Rendering

Next.js 14 allows for more flexible rendering strategies:

1. Dynamic Rendering: Next.js can automatically choose between static and dynamic rendering based on the use of dynamic functions.
2. Partial Prerendering: This experimental feature allows you to combine static and dynamic content in a single page.

Here’s an example of dynamic rendering:

//app/dynamic-example/page.tsx
import { unstable_noStore as noStore } from 'next/cache'
async function getData() {
  noStore()
  const res = await fetch('https://api.example.com/data')
  if (!res.ok) {
    throw new Error('Failed to fetch data')
  }
  return res.json()
}
export default async function DynamicPage() {
  const data = await getData()
  return <div>{data.title}</div>
}

This page will be rendered dynamically at request time due to the use of noStore().

Performance Considerations

When deciding between SSR and SSG in Next.js 14, consider:

1. Streaming: Next.js 14 supports streaming, allowing you to progressively render UI from the server.
2. React Server Components: These can significantly reduce the JavaScript sent to the client.
3. Automatic Code Splitting: Next.js automatically code-splits your application.

To optimize performance:

• Use the loading.js file for instant loading states
• Implement proper caching strategies
• Optimize images using the Next.js Image component

SEO Impact

Both SSR and SSG can provide excellent SEO benefits in Next.js 14:

• SSR ensures search engines always see the latest content
• SSG provides fast-loading pages, which is a positive ranking factor

For optimal SEO:

1. Use metadata files for better SEO control
2. Implement structured data
3. Ensure proper heading hierarchy
4. Optimize for Core Web Vitals

Conclusion

Next.js 14 with the App Router simplifies the implementation of SSR and SSG while providing more flexibility in rendering strategies. SSR is ideal for dynamic, personalized content that changes frequently, while SSG excels at delivering fast, static content at scale. The new dynamic rendering and experimental partial prerendering features offer even more options for optimizing your application.

Remember, you’re not limited to one approach – Next.js 14 allows you to use different rendering strategies within the same project, giving you the flexibility to optimize each page according to its needs.

Additional Resources

• Next.js 14 Documentation on Rendering
• Understanding Server and Client Components
• Data Fetching in Next.js 14

By leveraging the right rendering strategy for each part of your application, you can create fast, scalable, and SEO-friendly websites with Next.js 14.