Optimizing SEO with Server-Side Rendering (SSR) and Static Site Generation (SSG)

While search engines have the capability to index JavaScript-heavy Single Page Applications (SPAs), they don't always do it optimally.

Traditional web apps render content on the client-side, which implies that the initial HTML that the server sends is almost empty. Search engine crawlers have to wait for the JavaScript to load and execute to fetch the actual content. Consequently, this delayed loading can lead to some pages being missed or misindexed.

To overcome these limitations, we use Server-Side Rendering (SSR) or Static Site Generation (SSG). Both these techniques generate HTML either at build time or request time. This makes the content immediately available for search engine bots, enhancing the SEO potential of your application.

In this article, we will delve into:

• The fundamentals of SSR and SSG
• How they contribute to SEO optimization
• The appropriate use-cases for SSR and SSG
• Examples with frameworks such as Next.js, Astro, and Nuxt
• Common pitfalls and best practices to consider

The Impact of Client-Side Rendering on SEO

Googlebot is capable of rendering JavaScript, but it often does so inconsistently and at a slower pace. Furthermore, social media crawlers like those for Slack or LinkedIn often don’t execute JavaScript at all. This means that an empty <div id="root"> is a missed opportunity for indexing.

Moreover, dynamic content that loads too late might not get indexed at all, leading to decreased visibility in search engine results.

SSR vs SSG — A Comparative Analysis

| Feature | SSR (Server Side Rendering) | SSG (Static Site Generation) | |--------------|-----------------------------------|--------------------------------| | When Rendered | On request (per user) | At build time (once) | | SEO Friendly | Yes | Yes | | Use Case | Dynamic content, user-specific | Blogs, docs, mostly-static | | Example | Product page with live price | Marketing homepage |

Insights into Next.js

Next.js supports both SSR and SSG.

Static Site Generation (SSG)

In SSG, the HTML is generated at build time and then reused on each request. It's beneficial for pages that can be shared amongst users in the same state, like a blog post.

Here's an example of a SSG page in Next.js:

export async function getStaticProps() {
  const posts = await fetchPosts(); // Fetch data at build time
  return { props: { posts } }; // Pass data to the page via props
}

Server-Side Rendering (SSR)

SSR is used when the content is user-specific or dynamic. The HTML is generated on each request.

Here's an example of a SSR page in Next.js:

export async function getServerSideProps(context) {
  const data = await fetchData(context.params.id); // Fetch data on each request
  return { props: { data } }; // Pass data to the page via props
}

Both techniques will pre-render the page to HTML, making it ready for search engine indexing.

Astro & SvelteKit

Astro

Astro is an innovative frontend framework that allows you to write less JavaScript. By default, all pages are SSG which makes Astro a great choice for content-heavy sites.

export async function getStaticPaths() {
  return [{ params: { slug: "seo-guide" } }]; // Define the paths that have to be statically generated
}

SvelteKit

SvelteKit is a framework built on Svelte and provides flexibility to choose between SSR, SSG, or hybrid rendering per route.

export const prerender = true; // Enables SSG

Advantages of SSR and SSG for SEO

Both SSR and SSG have significant benefits for SEO:

• They ensure immediate availability of content in HTML format.
• They contribute to a faster Time to First Byte (TTFB), which is a core web vital metric.
• They provide better support for crawlers and link previews.
• They allow greater control over meta tags, structured data, and canonical links.

Common Pitfalls to Avoid

While SSR and SSG have their benefits, they also have potential pitfalls:

• SSR pages without caching can be slower and more costly.
• SSG builds might not include new pages, leading to stale sitemaps.
• Improper <head> metadata can lead to missing title/meta on SSR.
• Absence of loading states can lead to a broken UX for slow loads.
• Forgetting to update canonical URLs for dynamic pages can lead to SEO issues.

Real-World Examples

Vercel.com

Vercel.com uses Next.js with a hybrid of SSR/SSG. The content pages are statically generated for optimal performance, while the dashboard and authentication are server-rendered to handle dynamic data.

Notion.dev

Notion.dev pre-renders its documentation with Astro. This results in instant loading with crawlable HTML, enhancing the SEO.

Bonus: Incremental Static Regeneration (ISR)

Next.js and some other frameworks also support Incremental Static Regeneration (ISR). This method allows you to update static content after it's been generated, without needing to rebuild the entire site.

export async function getStaticProps() {
  return {
    props: {},
    revalidate: 60 // Regenerate the page every 60 seconds
  }
}

ISR provides the best of both worlds, combining the performance of static sites with the freshness of dynamic content.

Conclusion: Render for Robots

SSR and SSG allow you to serve content the way search engines prefer: fast, clear, and complete. Don't leave your pages blank and expect crawlers to figure it out. Render once, reuse often, and ensure your content is visible the moment the page loads.

Remember, the best SEO isn't magic — it's the result of good engineering.