What is prerendering (for SEO)?

In the dynamic world of web development and digital marketing, prerendering is a powerful technique that can help significantly improve the loading speed of web pages. For CMOs and marketing managers striving for an optimized user experience and better SEO performance, implementing prerendering presents a unique opportunity. This introduction provides an overview of the important steps to apply prerendering effectively, aimed at increasing Web site speed and accessibility.

What is prerendering (and what are its benefits)?

Prerendering is a process in which a Web page is pre-loaded and executed even before a user actually requests it. This means that the page has already been fully rendered on the server and is ready to be displayed immediately as soon as a visitor opens the URL. It is a technique especially useful for speeding up load times and improving the user experience.

  1. Functioning of prerendering: Traditionally, a browser loads a Web page when a user enters a URL or clicks on a link. This process involves fetching HTML, CSS, JavaScript and other resources from the server, executing scripts and rendering the page in the browser. Prerendering modifies this sequence by pre-loading and rendering the Web page. Instead of waiting for a user to request the page, the page is processed on the server beforehand. This means that as soon as a user requests access to the page, most, if not all, elements of the page are already loaded and ready for display.
  2. Benefits to load times and user experience: The biggest benefit of prerendering is improved loading speed. Because the page is pre-rendered, the time and resources required to load and render the page in the user’s browser are significantly reduced. This results in faster access to content, which is especially important in an era when users expect Web pages to load almost instantly. A faster load time not only improves the user experience, but can also have a positive impact on SEO, as search engines prefer faster-loading websites.
  3. Benefits for SEO: Search engines appreciate websites that load quickly and efficiently. Therefore, prerendering can help improve search engine rankings. In addition, prerendering ensures that certain JavaScript frameworks are rendered before being served to Googlebot (this is the biggest benefit).
What is prerendering (for SEO)?

When is prerendering interesting?

Prerendering is particularly interesting in situations where speed and immediate accessibility are crucial. Consider high-traffic websites, for example, where every second of load time impacts user engagement and conversion rates. It is also useful for pages with complex or heavy content, such as large images or advanced scripts, which normally load more slowly.

  1. Websites with high traffic volumes: For websites that attract a significant number of visitors, such as popular news portals, online stores, or large blogs, every second saved on load time can significantly improve the user experience. In such cases, prerendering can help distribute the server load and manage spikes in Web traffic more efficiently.
  2. E-commerce platforms: For online stores where conversion is directly tied to the user experience, prerendering can be a critical factor. Faster load times can improve the customer experience, increasing the likelihood that visitors will move through the various stages of the purchase process without getting distracted or frustrated by slow performance.
  3. Interactive websites and web applications: Websites that contain heavy or complex interactive elements, such as online tools, games or interactive data visualizations, may benefit from prerendering. This is because such sites often take longer to load, and pre-rendering these elements can significantly reduce load times.
E-commerce platforms

When is it not interesting?

Prerendering is not always the ideal choice, especially in situations where websites depend on real-time data or personalized user experiences. When content changes dynamically based on user interactions or preferences, prerendering can be problematic because it pre-loads and executes content, which can result in displaying outdated or irrelevant information to the user.

For example, on a news website where headlines and stories change hourly, prerendering could result in displaying news that is already out of date by the time the user visits the page. Similarly, on an e-commerce Web site that makes personalized product recommendations based on user behavior, prerendering would not be effective because the recommendations would have to change as soon as the user interacted with the site.

Moreover, implementing prerendering may impose additional load on the server because preprocessing pages requires additional resources. For smaller websites or businesses with limited server capacity or technical resources, this can be a significant barrier. The additional server usage can lead to increased costs or reduced site performance, which can ultimately negatively impact both the user experience and overall effectiveness of the website.

Therefore, it is important to weigh the benefits of prerendering against the specific needs and dynamics of your website. In cases where content is highly dynamic or server resources are limited, alternative strategies for improving load speeds and user experience, such as lazy loading or asynchronous JavaScript, may be more appropriate.

Prerendering vs client/server/dynamic rendering

How does solution prerendering perform vs. client, server or dyanmic rendering? I contrast them below. Typically, there are several situations where a custom solution is ideal, but for standard scenarios you can find my advice below.

Prerendering versus server-side rendering

When considering prerendering and server-side rendering, it is important to understand the distinction between the two. Server-side rendering means that the entire page is generated on the server before it is sent to the browser. This is especially effective for SEO because search engines can more easily crawl and index the page. Prerendering, on the other hand, loads and renders the page in advance, making the content immediately available as soon as a user requests the page. The difference is in the timing of rendering: server-side rendering happens with each user request, while prerendering happens in advance.

Prerendering versus client-side rendering

Clientside rendering differs significantly from prerendering. In client-side rendering, the content is generated by the user’s browser, usually through JavaScript. This means that the page is loaded and rendered dynamically, providing flexibility for interactive Web sites. However, this can be detrimental to SEO because search engines may have trouble indexing this content. Prerendering offers a solution to this problem by pre-loading the page, making the content immediately accessible to both users and search engines.

Prerendering versus dynamic rendering

Dynamic rendering is a technique that provides a middle ground between server-side and client-side rendering. It offers the flexibility of client-side rendering, but with enhanced SEO capabilities. With dynamic rendering, the server chooses whether to render the content server-side or client-side based on the user type – a real person or a search engine bot. Prerendering is more of a “one-size-fits-all” solution, where the page is pre-rendered regardless of the user. This makes prerendering easier to implement, but potentially less flexible compared to dynamic rendering.

The differences at a glance

Here is a table explaining the differences between prerendering, server-side rendering, client-side rendering and dynamic rendering:

Rendering TypeDescriptionSEOUser Experience
PrerenderingLoads and renders the page in advance, making the content immediately available upon user request.Good for SEOFast loading times
Serverside RenderingGenerates the full page on the server with each user request, beneficial for SEO.Excellent for SEODepending on server capacity
Clientside RenderingRenders content in the user’s browser, usually with JavaScript, provides flexibility for interactive sites.Less beneficial for SEODynamic, interactive experience
Dynamic RenderingChooses based on user type whether content is rendered server-side or client-side, a balance between flexibility and SEO.Balancing flexibility and SEOAdapted to user type
Prerendering, serverside rendering, clientside rendering and dynamic rendering listed.

My roadmap for prerendering

Setting prerendering used to be something that required development per se, but with today’s tools, it is being made easier and easier to do. Personally, I like to use https://prerender.io/ for this purpose.

Step 1: Analyze the need for prerendering

  • Rate the website: Look at current load times and user experience. Identify pages that would benefit from faster load times.
  • Understand traffic: Analyze website traffic patterns. Are there peak hours when loading speed becomes a bottleneck?

Step 2: Choose the right prerendering tool

  • Research available options: Several prerendering tools and services are available. Choose a tool that fits your organization’s technical specifications and budget.
  • Test compatibility: Make sure the tool you choose is compatible with your current Web infrastructure and content management systems.

Step 3: Implementation planning

  • Create an implementation schedule: Determine a timeline for implementing prerendering. Consider a phased approach for large Web sites.
  • Technical Preparation: Work with your web development team to prepare the necessary technical modifications.

Step 4: Implement prerendering

  • Configure the chosen tool: Set up the prerendering tool according to your website’s specifications.
  • Test on a subset of pages: Start by implementing prerendering on a small number of pages to test its effectiveness.

Step 5: Optimization and adaptation

  • Monitor performance: Use analytics tools to measure the impact of prerendering on load times and user experience.
  • Make adjustments: Optimize the configuration based on the collected data and feedback.

Step 6: Rollout and continuous monitoring

  • Expand to more pages: If the initial results are positive, expand the prerendering to more pages.
  • Keep monitoring and improving: Continuous monitoring is essential to maximize the benefits of prerendering and to ensure compatibility with future Web site updates.

Step 7: Evaluation and feedback

  • Evaluate impact: Assess the overall impact of prerendering on SEO and user experience.
  • Gather feedback from users: Feedback from users can provide valuable insights for further improvements.
Keep monitoring and improving

This roadmap helps to successfully implement and manage prerendering, leading to faster load times and an improved user experience on your website.

Conclusion

Implementing prerendering is a strategic decision that can have a significant impact on a Web site’s performance and user experience. By following the step-by-step plan outlined, organizations can optimize their websites for both speed and SEO. This not only leads to better user engagement and satisfaction, but also improves search engine visibility. With the right approach and ongoing maintenance, prerendering can be a valuable part of an overall digital strategy.

Senior SEO-specialist

Ralf van Veen

Senior SEO-specialist
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I have been working for 10 years as an independent SEO specialist for companies (in the Netherlands and abroad) that want to rank higher in Google in a sustainable manner. During this period I have consulted A-brands, set up large-scale international SEO campaigns and coached global development teams in the field of search engine optimization.

With this broad experience within SEO, I have developed the SEO course and helped hundreds of companies with improved findability in Google in a sustainable and transparent way. For this you can consult my portfolio, references and collaborations.

This article was originally published on 12 December 2023. The last update of this article was on 28 December 2023. The content of this page was written and approved by Ralf van Veen. Learn more about the creation of my articles in my editorial guidelines.