What is rendering?

Rendering is the process in which Google (or a browser) converts the source code of a web page into the visual image that a user sees.
In other words, the time when all HTML, CSS, and JavaScript are loaded and merged into a page that is readable, not only by humans, but also by search engines.

In SEO, rendering means that Google is trying to understand how your content looks and which parts are important.
Only when a page is fully rendered can Google index everything that's visible.

How does rendering work exactly?

The rendering process consists of three steps that take place one after the other in rapid succession:

1. Loading HTML
   Googlebot reads the source code of your page and retrieves initial content.
2. Run CSS and JavaScript
   The layout (color, texture, layout) and interactive elements are loaded.
3. Visual Interpretation
   Google creates a picture of what the user would see and, based on that, determines the content that ends up in the index.

Some elements, such as menus or buttons that only load after JavaScript, may remain invisible to Google without good rendering settings.

Why is rendering important for SEO?

As an SEO specialist, I often see that websites are crawled well, but that Google does not provide the most important content sees because it only appears after a JavaScript load.
In that case, Google will only crawl a bare HTML page with no content, and then you can optimize what you want, but nothing will rank.

A well-rendered website ensures that:

• Google can read the entire content, including dynamic elements.
• Structured data is interpreted correctly.
• Core Web Vitals perform better because loading times are predictable.
• Important elements such as H1, text, and internal links are immediately visible.

Bottom line: Without proper rendering, Google won't fully understand your site.

Server-side vs. client-side rendering

There are two ways in which websites are rendered.

Server-side rendering (SSR)
Here, the entire HTML is built up on the server and sent directly to the browser (or Google).
Advantage: fast and easy to read by search engines.
Disadvantage: slightly heavier for the server on large websites.

Client-side rendering (CSR)
With CSR, the content is only built in the browser via JavaScript.
This is popular with frameworks like React or Vue, but can cause SEO issues if Google doesn't run the scripts.

That's why at Rank Rocket, I often work with hybrid rendering whether pre-rendering: The first version of the page is built server-side (so that Google can read everything), after which JavaScript adds dynamically to the rest.

How do I check that a page is rendering properly?

A simple way is via Google Search Console → URL inspection.
There, you can see exactly how Googlebot renders your page.

I'm mainly looking at:

• Whether the text and images are visible in the rendered view.
• Whether the most important SEO elements (H1, meta-tags, structured data) are displayed.
• Whether scripts cause error messages that prevent components from loading.

In addition, I often use tools such as Lighthouse, Rendertron whether Screaming Frog (JavaScript rendering) to get a complete picture.

How JavaScript affects rendering

JavaScript makes websites dynamic, but is also the biggest SEO challenge.
This is because Google has to use extra time and resources to run JavaScript, and that slows down the rendering process.

If Googlebot does not have enough crawl budget, it can happen that the JavaScript no longer fully loads.
Then Google misses crucial content.

That's why I always optimize JavaScript sites with:

• Lazy loading (but not on crucial texts)
• Deferred scripts (loading JS only after main content)
• Server-side rendering for important content

Rendering in practice at Rank Rocket

I regularly work with customers who use modern frameworks such as React or Vue.
In a webshop that ran entirely client-side, we saw in Search Console that hundreds of products were not indexed.

After implementing pre-rendering via SSR and adding structured data The product pages appeared in Google within two weeks.
Visibility doubled, and the click-through rate increased by 28%.

That proves once again: if Google can't render, Google can't understand you.