Differences Between Client Side Rendering (CSR) and Server Side Rendering (SSR) – Good SEO Practices

30.07.2020 Angelika Siczek
what are the differences between CSR and SSR?

What characterizes the functioning of the entire Internet? First of all, it is constantly changing. Algorithms in search engines are being updated, trends in website design, as well as methods of searching for information and many other factors are changing. However, there is one thing that does not change – the fact that only good websites rank high in search results and thus gain more visitors. Being ranked high in the search engine is a priority when doing online business. Search engines are the first pages of the web that users visit. Their mission is therefore to show visitors websites of the highest quality and best suited to the search term. So there is no better way to increase traffic to your website than by meeting these criteria. How can this be done?


What is SEO?

SEO stands for Search Engine Optimization, i.e. optimization of websites for the operation of search engines so that they appear as high as possible on the first page of search results. Although it may seem like a simple task at first, in practice it turns out to be a lengthy and often time-consuming process.


Search engines often change their operating strategies, which directly affects the process of creating websites. The need for positioning is therefore huge when you want to meet the current requirements. Fortunately, SEO experts are prepared for this and are constantly on the pulse of the moment. However, sometimes there are big changes that need to be looked at closely to reexamine how search engines work and what to do to align SEO best practices with them.


What is SSR and why is it important when building website visibility?

At the beginning of their operation, search engines analyzed websites by reading the HTML code generated by their websites. However, SSR – Server-Side Rendering – server-side rendering appeared relatively recently. As the name suggests, it is a method of generating the content of a web page right on the server side. Thanks to it, the browser receives the code from the page, and all its content appears on the computer screen immediately.


The web has thus become a rich application platform. All users expect pages to be interactive, dynamic, user-friendly and easy to use. How are these requirements met? Thanks to the creation of pages in HTML and using JavaScript. Many of today’s web pages are built with the most flexible techniques, including Client-Side Rendering (CSR). It has proved to be the best way to create modern, reliable, dynamic and scalable websites.


It should be remembered, however, that search engine crawlers are not full-fledged web browsers. While they have to navigate the vast web of content they analyze quickly, they haven’t supported JavaScript and CSR for years. This meant that if a site was using CSR to display content and other functionality, Googlebots didn’t notice it. Since this has been happening for quite a long time, SSR is a well-recognized content rendering method that ensures HTML content is easily accessible to modern search engine robots. Knowledge of SSR is therefore a basic function of an internet platform that you need to pay attention to when positioning.


While CSR is beneficial to the end user, it raises a number of questions about ensuring consistent ranking requirements for search engine results. A fair share of major sites, especially e-commerce sites, however, solved this problem by rendering the indexable content of the website on the server, and then switched to CSR to manage the page after it was loaded. SSR is an excellent and proven solution here. However, if it is not performed correctly, it may slow down the performance of the website, so be careful with it. It is worth mentioning here that the speed and efficiency of the website are extremely important for ensuring its high position in the search engine.


If a web search engine was able to index CSR generated pages, the easiest and fastest way would be to render the entire application using CSR. This is because it would be needed for the parts searched for. Currently, the largest search engines on the web are starting to support CSR in their indexing robots. However, despite this, we can still find many sites with very high search ranking results, even if they are not investing in SSR. So what makes them achieve such effects?


Modern entrepreneurs realize the importance of SEO and paid search engine results, i.e. SEM. It is thanks to such marketing activities that they are able to attract customers and generate income. It is also important to invest in new technologies, such as PWA (Progressive Web Applications), which rely heavily on CSR, but it cannot be conclusively determined whether they are much more effective than SSR. Nevertheless, thanks to PWA Studio, it is recognized as the future of the Internet, where SSR is no longer a difficult requirement to meet and where the current needs and concerns of online sellers are satisfied.


To mitigate the information chaos and see what is best to bet on, let’s look at the arguments for and against SSR at PWA Studio and learn about the selected options that will meet the high requirements of the modern Internet.


Is SSR necessary?

At the outset, it is worth noting that there is no simple answer to this question. There are arguments for and against SSR, especially in the context of PWA and JavaScript-based dynamic applications and sites. However, there is certainly no argument for the effectiveness of the SSR throughout the life of the Internet. SSR generates additional costs for us, so you should be sure how much SSR is still doing for us and whether it is worth investing in. By paying attention to modern web browsers and technologies, it is legitimate to question the importance and costs generated by the SSR. Especially when it becomes more and more obvious that search engines are able to index dynamic websites and constantly increase their effectiveness.


What arguments among companies speak for the implementation of SSR?

The SSR needs to be implemented as it worked before and is still working as it should. We don’t want to risk the failure of our business goals while the developers look forward to developing the history of SSR and CSR in the years to come.


Other modern and big tech companies are still investing in SSR, and not just because of SEO.


SSR is still needed when handling metadata for multimedia objects as SEM bots still don’t support JS.


In the case of agencies – the lack of a clear SEO strategy based on SSR hinders our ability to build trust with our clients / traders and invest more in PWA.


There is insufficient evidence that giving up or minimizing the use of SSR does not actually have a significant impact on SEO.


What arguments among companies persuade not to implement SSR?

Web development leaders often discourage SSR because poor implementations can degrade search performance and ranking. Especially in PWA, the user interface should be loaded as early as possible. SSR does a lot of preliminary calculations that the CSR client may not use at all.


There is a risk of blocking the platform or duplicating its code. The most important impressions of using PWA e-commerce are on the customer’s side. As a dynamic JavaScript application that runs in a native style, but cross-platform, SSR requires the experience to be implemented in two different places – server and CSR, and unfortunately its logic cannot be reused. The solution to this problem is to use a server that can render HTML generated by the user interface. NodeJS is a good server for this, as it can directly run JavaScript UI code and generate HTML responses. Unfortunately, this blocks developers from a specific technology of the entire backend.


SSR increases the TCO of a site due to additional technical and development requirements and the need for continuous integration. While it’s easier than it used to be, it’s also some extra work to write code that runs in two different environments.


The costs to SSR are hard to justify as search engines keep getting better at indexing the dynamic sites that are most important in the online world.


What SSR solutions can be used in PWA Studio?

Even though there are tons of solutions and areas for improvement today, PWA Studio still supports SSR. Why is this happening? Find out about the current SSR implementation options in PWA Studio that PWA Studio Community members have reached.


1. UPWARD – provides the ability to easily render SSR data and page metadata. This serves the simple use case that PWA advocates consider best practice. For more complex requirements (e.g. full-page rendering of React applications), there are other solutions that will certainly make your work easier.


2. Pre-rendering with headless browser crawler browser – Jordan Eisenburger (Experius) recommends Renderton, which is non-invasive in the build process. However, novice users may find it difficult to configure it nonetheless. It is the tool used on the Eleganza website and will open soon as SEOSnap.


3. Shane Osbourne (JH) recommends terminating React with ReactDOMServer early as this is a well known and frequently used approach. It is not only workable, but also efficient and fast. However, it requires a production web server NodeJS and other requirements imposed by Magento 2.


4. Niklas Wolf (Mothership) recommends targeting search engine bots to services like Prerender.io to handle pre-made HTML pages. This approach is similar to the pre-rendering used by Experius, except that it uses the SaaS pre-render rather than the standard renderer.


What is the future of PWA Studio and SSR?

The creators of PWA Studio are open to the needs of their users, so they understood that the minimum SSR solutions do not provide enough opportunities to start implementing new stores. However, they are sure that in the future, the SSR will have less importance on the Internet. Nevertheless, today they want to provide recipients with as many opportunities as possible.


The hope for everyone is that PWA Studio offers a simple SSR capability, thereby opening up server-side rendering rules that are part of the new extensibility. The developers want the PWA extension ecosystem to grow constantly and include server-side rendering options.


Please note that Magento relies heavily on extensibility. However, new tools and resources are still being delivered to the platform to further facilitate the work of developers and the associated costs. So ways are constantly being sought to improve the SSR history for online retailers and their partners. These include putting React SSR at the center, setting Rendertron as the preferred solution, increasing UPRARD SSR capabilities, and possibly even withdrawing UPWARD altogether. All changes are made in consultation with the community to deliver the best, scalable solutions that will ensure the most effective in its class SEO for each PWA Studio storefront. This is good news for everyone who uses this solution!

Have a question?

Write to us

    PDF, DOC, DOCX, JPG lub PNG (max 5MB)



    Andrzej Szylar

    Chief Executive Officer



    Magdalena Paczyńska-Kamienik

    HR Manager



    Aleksandra Bielawska-Clegg

    HR Business Partner



    Michał Duława

    New Business Developer



    Katarzyna Zajchowska

    Marketing Partner