Server-Side Rendering Vs Client-Side Rendering

Matthew Marley SEO

By Matthew Marley

  • 21/03/2023

For many web developers, choosing the right rendering approach for your website or web application is a critical decision. 

Server-side rendering (SSR) and client-side rendering (CSR) are the two primary methods, each with its own set of advantages and disadvantages. 

This article aims to provide an in-depth comparison of SSR and CSR, exploring their respective strengths and weaknesses, and offering guidance on when to choose one over the other. 

Additionally, we will touch upon some popular hybrid rendering techniques, such as isomorphic or universal rendering, which combine the benefits of both SSR and CSR to create a more balanced solution. 

By understanding these rendering approaches and their implications, you can make an informed decision on the most suitable method for your web application, ensuring an optimal user experience and meeting your project’s performance goals.

What is server-side rendering? 

Server-side rendering, often abbreviated as SSR, is a technique employed in web development whereby the content of a webpage is generated on the server rather than the client’s browser. 

This approach can offer several benefits, such as improved performance, better search engine optimisation (SEO), and a more consistent user experience.

When a user requests a webpage, the server processes the request and generates the HTML, CSS, and JavaScript content before sending it to the client’s browser. 

The browser then renders this content, displaying the webpage to the user. Because the server handles the initial rendering, the webpage can load more quickly, which can be particularly beneficial for users with slow internet connections or less powerful devices.

How does server-side rendering work 

Server-side rendering (SSR) works by generating the HTML, CSS, and JavaScript content for a webpage on the server before sending it to the client’s browser. Here’s an overview of the SSR process:

Client request: When a user visits a website, their browser sends a request to the server for the content of that webpage.

Server processing: The server processes this request, typically using a back-end programming language (such as Node.js, PHP, or Ruby) and a template engine (like EJS, Handlebars, or Jinja). 

It retrieves data from a database if needed, and uses this data to generate the HTML, CSS, and JavaScript content for the webpage.

HTML generation: The server creates a fully-formed HTML document, complete with the necessary CSS and JavaScript code. This document represents the initial state of the webpage, with all the dynamic content and interactivity already in place.

Sending to the browser: The server sends the fully-formed HTML document to the client’s browser, which then renders the content and displays it to the user.

Browser rendering: The browser parses and executes the received HTML, CSS, and JavaScript, rendering the webpage. If there’s any client-side JavaScript that needs to run after the initial render, it does so at this stage, enhancing the interactivity and responsiveness of the webpage.

User interaction: The user can now interact with the fully rendered webpage. Any subsequent requests for new content or actions that involve server communication are handled via AJAX (Asynchronous JavaScript and XML) calls, which allow for data exchange without the need for a full page refresh.

By rendering the webpage on the server, SSR can improve the initial loading speed, enhance search engine optimisation (SEO), and provide a more consistent user experience, particularly for users with slower internet connections or less powerful devices.

Server Side Rendering Vs Client Side Rendering: The Ultimate Guide

What are the advantages of server-side rendering

Server-side rendering (SSR) offers several advantages in web development, including:

Improved performance:

SSR can improve the initial loading speed of a webpage, as the browser receives a fully-formed HTML document with all the necessary CSS and JavaScript from the server. 

This reduces the amount of client-side rendering and processing needed, providing a faster experience for users, especially those with slow internet connections or less powerful devices.

Better search engine optimisation (SEO)

Search engine crawlers can more easily index and understand content that is rendered on the server. 

This can lead to higher search rankings and increased visibility for a website. Some crawlers may struggle with indexing client-side rendered content, making SSR particularly important for SEO purposes.

Consistent user experience

SSR can provide a more consistent user experience across different devices and browsers, as the initial rendering is done on the server. This ensures that users see the same content regardless of their device capabilities or browser support for certain JavaScript features.

Faster time to first paint (TTFP)

With SSR, the time it takes for the first meaningful content to appear on the screen is reduced, as the browser receives a pre-rendered HTML document. This can create a better perceived performance for users, as they see content more quickly.

Enhanced social media sharing

SSR-generated webpages often provide better support for social media sharing, as the meta tags required for generating rich previews (such as title, description, and image) are already present in the server-rendered HTML. 

This can lead to more accurate and appealing previews when users share the webpage on social media platforms.

Easier debugging

Debugging can be simpler with SSR, as developers can more easily identify and fix issues on the server side. This can lead to a more stable and robust application overall.

While SSR offers these advantages, it’s important to consider the trade-offs as well. For instance, SSR can increase the load on the server, as it needs to handle the rendering process for each user request. 

Additionally, implementing SSR can be more complex than client-side rendering, particularly in cases where real-time updates and interactions are required.

What are the disadvantages of server-side rendering

While server-side rendering (SSR) offers several benefits, it also comes with some disadvantages:

Increased server load

With SSR, the server has to handle the rendering process for each user request. This can increase the load on the server, potentially leading to slower response times and reduced performance if not properly optimised or scaled.

Complexity

Implementing SSR can be more complex than client-side rendering, especially in cases where real-time updates and interactions are required. 

Developers need to manage both server-side and client-side code, which may increase the overall development and maintenance effort.

Slower interactivity

Although SSR can improve the initial loading speed of a webpage, it may result in slower interactivity, as client-side JavaScript still needs to be executed after the initial render. 

This can impact the user experience, particularly if the JavaScript takes a significant amount of time to load or execute.

Increased development time

Due to the added complexity of SSR, development time can be longer compared to client-side rendering. 

This is because developers need to manage both server-side and client-side code, often using different languages and frameworks.

Server dependency

SSR relies on the server for rendering, which makes the application more dependent on the server’s uptime and availability. 

In the event of server issues, the entire application may become unavailable, unlike client-side rendering, where some functionality may still work even if the server is down.

Less efficient use of client resources

With SSR, the server performs the rendering process, which may not make the best use of the client’s processing capabilities. 

Modern devices have powerful processors that can handle client-side rendering efficiently, and by relying on SSR, you may not be fully utilising these resources.

Caching limitations

Caching can be more challenging with SSR, as the server generates unique content for each user request. This may limit the effectiveness of caching strategies that rely on static, pre-rendered content.

Despite these disadvantages, SSR can still be a valuable approach in certain situations, such as when search engine optimisation (SEO) is a priority or when targeting users with slow internet connections or less powerful devices. 

It’s essential to consider the specific requirements of your web application and weigh the pros and cons before choosing between SSR and client-side rendering.

When should you use server-side rendering

Server-side rendering (SSR) can be an appropriate choice for web applications in several situations:

SEO is a priority

If search engine optimisation (SEO) is crucial for your website, SSR can be beneficial, as it ensures that search engine crawlers can easily index and understand your content. This can lead to better search rankings and increased visibility.

Improved performance on slow connections or low-powered devices

SSR can enhance the initial loading speed of a webpage, which is especially helpful for users with slow internet connections or less powerful devices. 

By delivering a fully-formed HTML document from the server, you can reduce the amount of client-side rendering and processing required, providing a faster experience for these users.

Consistent user experience

If you want to ensure a consistent user experience across different devices and browsers, SSR can be a good choice. The server handles the initial rendering, so users see the same content regardless of their device capabilities or browser support for certain JavaScript features.

Faster time to first paint (TTFP)

If you want to improve the perceived performance of your website by reducing the time it takes for the first meaningful content to appear on the screen, SSR can help. By providing a pre-rendered HTML document, the browser can display content more quickly

Enhanced social media sharing

SSR-generated webpages often provide better support for social media sharing, with the necessary meta tags for generating rich previews already present in the server-rendered HTML. This can lead to more accurate and appealing previews when users share the webpage on social media platforms.

Web applications with limited interactivity

SSR can be a good choice for web applications that have limited interactivity and do not require frequent real-time updates. In these cases, the additional complexity of client-side rendering may not be necessary.

It’s essential to consider the specific requirements of your web application and weigh the pros and cons before choosing between SSR and client-side rendering. 

Keep in mind that you can also use hybrid approaches, such as isomorphic or universal rendering, which combine the benefits of both SSR and client-side rendering

What is client side rendering 

Client-side rendering (CSR) is a web development approach where the content and layout of a webpage are generated and rendered in the user’s browser, using JavaScript, rather than on the server. 

In this technique, the server sends a minimal HTML file along with the necessary CSS and JavaScript files to the browser. The browser then executes the JavaScript code to dynamically generate the content and display it to the user.

Here’s an overview of the CSR process:

Client request

When a user visits a website, their browser sends a request to the server for the content of the webpage.

Server response

The server responds with a minimal HTML file, which includes links to the necessary CSS and JavaScript files, instead of a fully-formed HTML document

Browser rendering

The browser downloads and parses the CSS and JavaScript files. The JavaScript code generates the content and layout of the webpage dynamically, updating the Document Object Model (DOM) in the browser.

User interaction

The user interacts with the fully rendered webpage. Any subsequent requests for new content or actions that involve server communication are typically handled via AJAX (Asynchronous JavaScript and XML) calls, which allow for data exchange without the need for a full page refresh.

Client-side rendering can offer benefits like reduced server load, faster subsequent page loads, and more interactive user experiences. 

However, it may have drawbacks, such as slower initial load times, potential SEO challenges, and reliance on the user’s device capabilities and browser compatibility.

How does client side rendering work 

Client-side rendering (CSR) works by generating and rendering the content and layout of a webpage directly in the user’s browser, using JavaScript. Here’s an overview of the CSR process:

Client request

When a user visits a website, their browser sends a request to the server for the content of the webpage.

Server response

The server responds with a minimal HTML file, which includes links to the necessary CSS and JavaScript files. This minimal HTML file typically contains a basic structure and a root element where the content will be rendered.

Loading assets

The browser downloads the linked CSS and JavaScript files. The JavaScript files may include libraries or frameworks (such as React, Angular, or Vue.js) and custom application code.

Browser rendering

The browser parses the CSS files to apply styles to the webpage. It also parses and executes the JavaScript code, which generates the content and layout of the webpage dynamically. 

The JavaScript manipulates the Document Object Model (DOM) in the browser, updating the page with the generated content.

Data fetching

If the webpage requires data from an external source, such as an API or a database, the JavaScript code typically makes AJAX (Asynchronous JavaScript and XML) calls to fetch the data. 

Once the data is retrieved, the JavaScript code processes it and updates the DOM with the relevant content.

User interaction

The user can now interact with the fully rendered webpage. Client-side rendering allows for more interactive and responsive user experiences, as updates to the DOM can be made without the need for a full page refresh. 

Any subsequent requests for new content or actions that involve server communication are usually handled via AJAX calls, enabling smooth data exchange without disrupting the user’s experience.

While CSR can offer benefits such as reduced server load, faster subsequent page loads, and more interactive user experiences, it also has potential drawbacks. 

These include slower initial load times, reliance on the user’s device capabilities and browser compatibility, and potential challenges with search engine optimisation (SEO).

Server Side Rendering Vs Client Side Rendering: The Ultimate Guide

What are the advantages of client side rendering

Client-side rendering (CSR) offers several advantages in web development, including:

Reduced server load

With CSR, the server’s primary responsibility is to deliver the static assets (HTML, CSS, and JavaScript files) to the client. 

The browser handles the rendering process, reducing the load on the server and potentially leading to faster response times and better server performance.

Faster subsequent page loads

Once the necessary JavaScript files are loaded and cached in the browser, subsequent page loads within the same web application can be faster, as the browser can generate and display new content without additional requests to the server.

Rich interactivity and responsiveness

CSR allows for more interactive and responsive user experiences, as updates to the Document Object Model (DOM) can be made without the need for a full page refresh. 

This can result in smoother transitions and improved user experience, particularly in single-page applications (SPAs).

Real-time updates

CSR makes it easier to implement real-time updates and interactions within a web application, as the browser can fetch and display new data without refreshing the entire page. 

This can be particularly useful for applications like social media platforms, chat applications, or live dashboards.

Offline functionality

With CSR, it is possible to implement offline functionality by caching data and assets in the browser. 

This allows users to continue interacting with the web application even when they temporarily lose internet connectivity.

Easier scaling

As the rendering process is offloaded to the client’s browser, server resources can be better utilized for other tasks, such as handling API requests or managing the database. 

This can make it easier to scale the application to handle increased user traffic. However, it’s important to consider the potential drawbacks of CSR as well, such as slower initial load times, potential SEO challenges, and reliance on the user’s device capabilities and browser compatibility. 

Balancing the pros and cons of CSR and server-side rendering (SSR) is crucial when choosing the most appropriate approach for your web application.

What are the disadvantages of client side rendering

Client-side rendering (CSR) comes with several disadvantages that should be considered when developing a web application:

Slower initial load times

With CSR, the browser has to download, parse, and execute the JavaScript files before rendering the content. This can result in slower initial load times compared to server-side rendering (SSR), which delivers a pre-rendered HTML document to the browser.

SEO challenges

Search engine crawlers may struggle to index and understand content that is generated and rendered on the client side. 

Although search engines like Google have improved their ability to process JavaScript, relying solely on CSR can still pose risks for search engine optimisation (SEO) and visibility.

Device and browser compatibility

CSR relies on the user’s device capabilities and browser compatibility with the JavaScript code. 

Users with older devices or browsers that don’t fully support modern JavaScript features may experience performance issues or even be unable to view the content.

Increased client-side processing

CSR requires the user’s device to handle the rendering process, which may lead to increased processing time and memory usage. 

This can negatively impact the user experience, particularly for users with less powerful devices or slow internet connections.

Inefficient use of server resources

In CSR, the server primarily serves static assets, which may not be the most efficient use of server resources. 

In contrast, server-side rendering (SSR) leverages the server’s processing power to generate the content, which can lead to faster initial load times and more efficient resource usage.

Less consistent user experience

As CSR relies on the client’s device and browser capabilities, the user experience may vary depending on factors such as processing power, internet connection speed, and browser compatibility. This can lead to a less consistent user experience compared to SSR.

Security concerns

With CSR, more application logic is exposed to the client side, which may increase the risk of security vulnerabilities if not properly managed. Developers should ensure that sensitive data and critical operations are securely handled on the server side.

When choosing between CSR and SSR, it’s important to consider the specific requirements of your web application and weigh the pros and cons of each approach. 

In some cases, a hybrid approach that combines the benefits of both CSR and SSR, such as isomorphic or universal rendering, may be the most suitable solution.

When should you use client side rendering 

Client-side rendering (CSR) can be an appropriate choice for web applications in several situations:

Single-page applications (SPAs)

CSR is particularly well-suited for SPAs, where the user interacts with the application without triggering full page reloads. CSR enables smooth navigation and a more app-like experience by dynamically updating the content in the browser.

Rich interactivity and responsiveness

If your web application requires a high level of interactivity and responsiveness, CSR can provide a better user experience by allowing updates to the Document Object Model (DOM) without a full page refresh.

Real-time updates

For applications that require real-time updates and data fetching, such as chat applications, social media platforms, or live dashboards, CSR can facilitate seamless updates without disrupting the user’s experience.

Offline functionality

If your web application needs to support offline functionality, CSR allows you to cache assets and data in the browser, enabling users to continue interacting with the application even when they temporarily lose internet connectivity.

Reduced server load

If you want to reduce the load on your server and rely more on the client’s processing capabilities, CSR can help by offloading the rendering process to the user’s browser.

Web applications with extensive client-side logic

For applications that have a significant amount of client-side logic, such as complex calculations, visualizations, or animations, CSR can be more efficient and provide better performance.

However, it’s essential to consider the potential drawbacks of CSR, such as slower initial load times, potential SEO challenges, and reliance on the user’s device capabilities and browser compatibility. 

Balancing the pros and cons of CSR and server-side rendering (SSR) is crucial when choosing the most appropriate approach for your web application. 

In some cases, a hybrid approach, such as isomorphic or universal rendering, may be the most suitable solution.

Conclusion

Both server-side rendering (SSR) and client-side rendering (CSR) have their respective advantages and disadvantages, and the choice between them depends on the specific requirements and goals of your web application.

SSR is particularly beneficial when search engine optimisation (SEO), faster initial load times, and consistent user experience across devices and browsers are priorities. 

It can also be more suitable for applications with limited interactivity and those targeting users with slow internet connections or less powerful devices.

On the other hand, CSR is well-suited for single-page applications (SPAs), web applications with rich interactivity and responsiveness, and those requiring real-time updates or offline functionality. CSR can help reduce server load and enable smoother, more app-like experiences.

In some cases, a hybrid approach, such as isomorphic or universal rendering, may provide the best of both worlds by combining the benefits of SSR and CSR. 

This approach can deliver the advantages of SSR, such as improved SEO and faster initial load times, while still offering the interactivity and responsiveness of CSR.

Ultimately, it’s essential to carefully consider the specific needs of your web application, and weigh the pros and cons of each rendering approach before making a decision. 

This will help ensure that you choose the most appropriate solution for delivering an optimal user experience and meeting your web application’s performance goals.