Server-Side Rendering vs. Client-Side Rendering: SEO & Performance Comparison

Server-Side Rendering vs. Client-Side Rendering: SEO & Performance Comparison

May 14, 2024

Visiting a website through your browser is super easy—all you need to do is type the URL into your browser and hit Enter, and the site will be displayed. Seems simple, right? Well, have you ever wondered what happens in between? How does just a URL get converted into a website full of beautiful fonts, images, layouts, and videos? It’s because of rendering.

So What is Rendering in Browsing?

Rendering, in itself, is the process of generating a visual representation from a set of data or instructions. In the context of browsing or web development, rendering occurs the moment you type a URL and hit Enter. It is how data or instructions are turned into a visual display.
When you type a URL in the address bar, your browser sends a request to the server where your site is being hosted, and looks for the content associated with the URL you entered. The server then responds to the request by sending back files to the browser. These files typically include HTML, CSS, JavaScript, images, and other resources necessary to render the web page. Once the browser receives these files, it begins the rendering process.

The Rendering Process In Browser Involves:

  • Parsing HTML to construct the Document Object Model (DOM).
  • Parsing CSS to compute styles and create the CSS Object Model (CSSOM).
  • Combining the DOM and CSSOM to create the Render Tree.
  • Calculating the layout of each element.
  • Painting the pixels on the screen based on the layout and styles.

Indeed, it’s quite remarkable how quickly the rendering process occurs. Despite its complexity, modern web browsers execute these steps in a fraction of a second, allowing web pages to load almost instantly.

What is a Render Tree in the Website Rendering Process?

The Render Tree is the blueprint that helps the browser construct the final visual representation of the web page that you see on your screen. This helps the browser understand what needs to be drawn on the screen and how to arrange and position the visible elements. It excludes any elements that are hidden or not meant for display, such as those affected by CSS properties like “display: none” or “visibility: hidden”.

For example, imagine you’re building a house, and the blueprint only shows the rooms, walls, and other visible structures, but not the hidden pipes or wiring behind the walls. Similarly, the render tree shows only the visible elements on a web page, like text, images, buttons, and other components that the user can see and interact with.

Types of Rendering for a Web Page

When it comes to rendering web pages, there are primarily two types: Server-Side Rendering (SSR) and Client-Side Rendering (CSR).

Note: These two rendering approaches have their pros and cons, and the choice between them depends on factors such as the complexity of the application, performance requirements, and SEO considerations. In some cases, a hybrid approach, known as Server-Side Rendering with Client-Side Hydration (SSR with CSR), is also used to combine the benefits of both approaches.

Now, let’s understand each type in details.

What is Server-Side Rendering (SSR)?

Server-Side Rendering (SRR) is a technique used in web development process where the server does all the rendering of a webpage. This increase the initial load time of the page as the browser doesn’t have to do anything, as it receive the fully rendered HTML content from the server.
If you are still unclear about SRR, let me explain to you in simpler words.
Imagine you are hosting a party at your house. Now you can do two things: prepare everything in advance before your guests’ arrival, or wait and start preparing in front of them.
You guessed it right, server-side rendering is like Server-Side Rendering is like preparing everything before your friends arrive. In this context, the server prepare (render) everything in advance in the server, and send the final HTML content to the browser.
This significantly improves the page load speed, which also improves the user experience, especially for users with less powerful devices, and slower internet connections. SSR rendering also helps in SEO as search engines, like Google and Bing, can easily crawl and index the pre-rendered content generated on the server.

Server Side Rendering Process for a Web Page

How Server-Side Rendering Works?

Server-Side Rendering Works in the Following Steps:

  • Client Request: When a user requests a web page, the request is sent to the server.
  • Server Rendering: On the server-side, the application code (e.g., React, Vue, or Angular) is executed, and the initial state of the page is rendered into HTML.
  • HTML Generation: The server generates the complete HTML markup of the rendered page, including the necessary CSS and JavaScript files.
  • Response Sent: The server sends the pre-rendered HTML to the client’s browser.
  • Client Hydration: Once the browser receives the pre-rendered HTML, it can quickly display the page. Then, the client-side JavaScript takes over, attaching event handlers and making the page interactive.

The main advantages of Server-Side Rendering are:

Better Initial Load Performance: Since the server sends a fully rendered page, the initial load time is faster. This provides a better user experience for users who have weak internet connection or slower devices.

Note: In some cases, Server-Side Rendering (SSR) can result in slower initial load times when it involves resource-intensive tasks such as database queries or external API calls.

Search Engine Optimization (SEO): Search engines can easily crawl and index the pre-rendered content, which can improve the website’s SEO performance.

Consistent Rendering: SSR ensures that the initial rendering on the server and the subsequent rendering on the client are consistent, reducing the risk of mismatches or flickering. By doing the initial preparation on the server, SSR ensures that what the user sees first is exactly what you intended, without any flickering or mismatches.

How to Implement Server-Side Rendering?

To implement Server-Side Rendering (SSR) in your website, you can follow these steps:

    • Choose a Framework: First, you need to select a special tool or framework that supports server-side rendering. Some of the popular options include Next.js for React websites, Nuxt.js for Vue.js websites, or Angular Universal for Angular websites.
    • Set Up Your Server: You need to install the necessary software and tools on your server computer.
    • Build Your Website: Using the framework you chose, you can start building your website. You need to add all the content, images, and functionality you want your website to have.
    • Implement Server-side Rendering: This is where the magic happens! You’ll write special instructions (code) on your server to take the website content you’ve built and prepare it as a complete, pre-rendered package before sending it to your visitors’ browsers.
    • Handle Data Fetching: Sometimes, your website might need to fetch additional data from external sources before it can be fully rendered.

For example, for an e-commerce website, the server needs to fetch additional data like product information, prices, and images. Similarly for a social media profile, profile information, posts, and other details need to be retrieved. For that, you’ll need to write code to handle this data fetching process on the server.

    1. Optimize Performance: Now, you’ll need to optimize your server-side rendering implementation to ensure it runs smoothly and quickly.
    2. Test and Debug: Before serving your website to visitors, you’ll need to thoroughly test it across different browsers and devices. If you find any issues or bugs, you’ll need to debug them.
    3. Deploy Your Website: Once everything is tested and ready, you’ll need to deploy your server-side rendered website to a live server.
    4. Monitor and Maintain: Even after deployment, you’ll need to monitor your website’s performance, security, and stability. Regular maintenance and updates will be necessary to keep your website running smoothly.

Server-Side Rendering Frameworks and Tools

Server-side rendering frameworks are tools that help website developers with the process of rendering web pages on the server. They make it easier to generate the pre-rendered HTML before sending it to the browser.

Some popular server-side rendering frameworks include:

  • Vue.js: A JavaScript framework that can be used to build user interfaces, including rendering them on the server.
  • React.js: A JavaScript library that allows developers to create reusable UI components that can be rendered on the server.
  • Ember.js: A complete JavaScript framework for building web applications, which includes tools for server-side rendering.
  • Angular: A popular JavaScript framework that has a tool called Angular Universal for server-side rendering.

These frameworks often work together with backend JavaScript frameworks like Express.js or Hapi. The backend framework handles the network requests from browsers, while the server-side rendering framework helps generate the pre-rendered HTML content before sending it back to the browser.

Is Server-Side Rendering Good For SEO, and How?

Yes, Server-Side Rendering (SSR) is generally considered good for Search Engine Optimization (SEO). Here’s how SSR can benefit SEO:

  • Crawlability: Search engine crawlers (like Google Bot) are better able to crawl and understand the content rendered on the server-side. When a website is rendered entirely on the client-side (using JavaScript), search engines may have difficulty crawling and indexing the content, as they don’t always execute JavaScript during the crawling process. With SSR, the crawlers can easily access the fully rendered HTML, improving the website’s visibility and indexability.
  • Faster Initial Load: SSR provides a faster initial load time for users since the server sends a fully rendered page to the browser. This improved performance can indirectly benefit SEO, as search engines consider page speed as a ranking factor.
  • Semantic HTML: SSR enables the generation of semantic HTML markup on the server, which can help search engines better understand the content structure and context. This can lead to more accurate indexing and potentially improved rankings.
  • Preview and Sharing: When content is rendered on the server, it can be easily previewed and shared on social media platforms or messaging apps. This improved previewing and sharing capability can lead to increased visibility and potential backlinks, which are important for SEO.
  • Accessibility: Since the initial content is rendered on the server, it’s more accessible to users with disabilities or those using older devices or browsers that may not fully support JavaScript. Improved accessibility can indirectly benefit SEO by providing a better user experience.

Note: it’s important to note that while SSR can provide SEO benefits, it’s not a silver bullet for ranking well in search engines. Other factors, such as high-quality content, backlinks, technical optimization, and overall user experience, also play crucial roles in determining a website’s search engine rankings.

Additionally, not all websites or applications may require SSR for SEO purposes. For example, single-page applications (SPAs) that heavily rely on client-side rendering can still be optimized for search engines using techniques like pre-rendering or server-side rendering at build time (known as static site generation).

Ultimately, the decision to implement SSR should be based on the specific requirements of the website or application, taking into account factors such as the target audience, content type, and the trade-offs between development complexity and potential SEO benefits.

How to Know If My Site is Using Server-Side Rendering (SSR)?

  • View Page Source: Right-click on your webpage and select “View Page Source” or “View Source” option in your web browser. Look through the HTML code of your webpage. If you see a fully rendered HTML structure with content in it, including dynamic content, it’s likely that your site is using SSR.
  • Inspect Network Requests: Open your browser’s developer tools (usually by pressing F12 or right-clicking on the page and selecting “Inspect” or “Inspect Element”), then go to the “Network” tab. Refresh the page and observe the network requests. If you see HTML files being fetched from the server on initial page load, it indicates that SSR might be in use.
  • Check Response Headers: In the Network tab of your browser’s developer tools, select the initial HTML request. Check the response headers for any indication of server-side rendering. Look for headers like “X-Powered-By” or custom headers that might indicate the use of SSR frameworks like Next.js or Nuxt.js.
  • JavaScript Disabled Test: Temporarily disable JavaScript in your browser settings and reload the page. If you can still see the content of your website, it’s likely that SSR is being used because the content is rendered on the server before being sent to the client.
  • View Page Load Behavior: Observe the behavior of your website during page load. If the content appears quickly and is visible before any JavaScript is executed, it suggests SSR. If you see a loading spinner or blank page before content appears, it might indicate client-side rendering (CSR).
  • Check the Framework or CMS Documentation: If you’re using a specific web framework or content management system (CMS) like React, Vue.js, Angular, or WordPress, check their documentation or configuration settings. Many of these platforms provide SSR capabilities, and they often have documentation on how to enable or configure it.

Limitations and Disadvantages of Server-Side Rendering

It goes without saying, Server-Side Rendering (SSR) brings an abundant of advantages of speed, SEO, and user-experience. However, not everything are bells and whistles over here.

Like all things, SSR does have its limitations, and disadvantages.

It May Increase the Server Load: With SSR, the entire application need to be rendered on the server. This can overload the server when your website is getting high traffic. As a result, it can reduce the response time of the server, while draining all the resources, leading to an increased cost on hosting and infrastructure.

It makes the Development Process More Complex: Web developers may have to shed extra sweat while coding for SRR as it required handling both server-side and client-side rendering logic. Consequently, the code base become more complex, and harder for maintenance, leading to more bugs.

 It May take Longer to Initial Page Load: While SSR speed up the initial load for the first rendered page, but that cannot be said much about further navigations within the pages, or any updates added within the application. This is because the client still needs to download and hydrate the JavaScript bundle for further interactions.

I know, it might be confusing for you. So, let’s understand it in a simpler way.

When you visit a website that uses SSR, it loads quicker as the whole layout and content are pre-rendered within the server itself. However, when you click on button, or a link, it triggers more contents to appear, or the layout to change. When you do that, the website send extra instructions (JavaScript code) for your browser to process. These extra code need additional time to process, which eventually may slow down the page loading speed.

It Leads to Potential Duplication of Effort: With SSR, the application needs to be rendered twice: once on the server and again on the client during hydration. This duplication of effort can lead to increased memory usage and potential performance issues, especially in complex applications.

It Increases Security Concerns: SSR introduces the need to handle user input and potential security vulnerabilities on the server, which can be more challenging to manage compared to a purely client-side application.

It has Limited Caching Opportunities: Server-rendered pages are often less cacheable than static assets, as they may contain dynamic content or user-specific data. This can lead to higher server loads and reduced caching benefits.

It May Make It Harder to Migrate: SSR solutions are often tied to specific frameworks or libraries, which can lead to vendor lock-in and make it harder to migrate or switch technologies in the future.

Why Server-Side Rendering (SSR) Raises Security Concern?

Handling user input and security vulnerabilities on the server side be more challenging due to several reasons:

Increased Attack Surface: When you use Server-Side Rendering (SSR), it’s the server that generates the initial contents. So, sensitive data such as form submission, login details, etc. are processed through the server. As a result, if there is any weaknesses or errors in server’s code, it can make it easier for hackers to retrieve those sensitive information.

Server-Side Logic: SSR typically involves more server-side logic to generate and serve dynamic content, handle form submissions, authenticate users, and manage session data. Managing and securing this server-side logic requires careful attention to prevent common security vulnerabilities such as injection attacks (e.g., SQL injection, XSS), authentication bypass, or sensitive data exposure.

Input Validation: Server-side input validation becomes crucial in SSR applications to ensure that user input is properly sanitized and validated before processing. Failure to adequately validate user input can lead to security vulnerabilities such as injection attacks or unintended data manipulation.

Session Management: SSR applications often require session management to maintain user state across requests. Managing sessions securely, including session tokens, expiration, and storage mechanisms, is essential to prevent session-related security vulnerabilities such as session fixation or session hijacking.

Data Protection: SSR applications may need to handle sensitive data on the server, such as user credentials, personal information, or payment details. Proper data protection measures, including encryption, secure storage, and access controls, are necessary to prevent data breaches or unauthorized access to sensitive information.

Dependency Management: SSR applications rely on various server-side dependencies, including frameworks, libraries, and third-party services. Keeping these dependencies up-to-date and secure is essential to mitigate security risks associated with vulnerabilities in outdated or insecure dependencies.

What is Client-Side Rendering (CSR)?

I guess you have a fair idea about Server-Side Rendering, and you might be thinking it is the best. However, not all sites are made for SSR.

If you are thinking of developing a modern website, with stunning designs, wide range of technology stacks, and a lot of functionalities to improve user-experience- then Client-Side Rendering is what you need. Before I explain to it in details, lets learn what is CSR.

Client-Side Rendering (CSR) is a modern web development approach where the initial HTML, CSS, and JavaScript are loaded from the server, but subsequent rendering and updates to the web page are handled by the client-side JavaScript running in the user’s web browser.

In a CSR application, the server sends a minimal HTML file along with the required JavaScript files. The JavaScript then takes over, creating and rendering the entire user interface (UI) within the browser. As the user interacts with the application, like clicking links or buttons, the JavaScript code dynamically updates the UI by manipulating the Document Object Model (DOM) without requiring a full page refresh.

How Client-Side Rendering Works in Browsing?

Here’s a typical flow of how CSR works:

  • The user requests a web page from the server.
  • The server responds with a basic HTML file containing a root element (e.g.,

    ) and the associated JavaScript files.

  • The browser loads and executes the JavaScript files.
  • The JavaScript code creates and renders the initial UI by manipulating the DOM.
  • When the user interacts with the application, the JavaScript code handles these events and updates the UI dynamically without requiring a full page reload.
  • If additional data is needed, the JavaScript code makes asynchronous requests (often using APIs like fetch or XMLHttpRequest) to retrieve the necessary data from the server.
  • The JavaScript code updates the UI based on the received data.

The Main Advantages of Using Client-Side Rendering in Browsing?

Client-Side Rendering (CSR) offers several benefits when it comes to developing a modern website:

Enhanced User Experience (UX): CSR applications provide a smooth and responsive user experience by eliminating full page refreshes. The UI updates dynamically, creating an app-like feel that users have come to expect from modern web applications.

Improved Performance: After the initial load, CSR applications typically have faster response times for user interactions since they don’t require a full page refresh. Only the necessary data and UI components are updated, reducing the amount of data that needs to be transferred between the client and server.

Separation of Concerns: CSR architectures allow for a clear separation of concerns between the front-end and back-end components of an application. The client-side code is responsible for rendering and managing the UI, while the server-side code handles data storage, retrieval, and API operations.

Code Reusability and Modularity: Many CSR frameworks and libraries, such as React, Angular, and Vue.js, promote a modular and component-based architecture. This makes it easier to create reusable UI components and maintain a well-structured codebase.

Offline Capabilities: With the help of technologies like Service Workers and client-side caching, CSR applications can be designed to work offline or in low-connectivity scenarios, providing a more resilient user experience.

Mobile-Friendly: CSR applications often deliver a mobile-friendly experience out of the box, as they are designed to work seamlessly across different devices and screen sizes.

Reduced Server Load: Since most of the rendering and UI logic happens on the client-side, CSR applications can potentially reduce the load on the server, allowing it to handle more concurrent users and requests.

SSR vs. CSR: Which is Better for SEO?

When it comes to Search Engine Optimization, Server-Side Rendering (SSR) has an upper hand over Client-Side Rendering (CSR). This is because, with SSR, the server generates a complete HTML Markup, making it easier for search engine crawlers to crawl and index HTML content.

Since SSR webpages initiate a faster loading of pages, this also increases your chances to rank as page loading speed is a crucial ranking factor for search engines like Google. On top of that, SSR also generates SEO-friendly markup such as metadata, structured data, and proper heading hierarchy, making it easier for search engines to easily understand the context of your contents, and index them faster.

CSR, on the other hand heavily relies on JavaScript to render the content on the client-side. Since search engine crawlers can only execute JavaScript in a limited manner, they may not fully render or index the content within the webpage. Plus, CRS applications have a slower initial load time, which can negatively affect SEO. Sometimes, when not implemented correctly, CSR can hinder search engines to understand the content and the website’s structure.

Here’s a comparison of SEO considerations between Server-Side Rendering (SSR) and Client-Side Rendering (CSR):

SEO ConsiderationsServer-Side Rendering (SSR)Client-Side Rendering (CSR)
IndexingProvides fully-rendered HTML content to search engines, making it easier for them to crawl and index the website.Requires additional steps such as prerendering or dynamic rendering to ensure that search engines can properly index the content.
Page Load SpeedTypically results in faster initial page load times since the server sends pre-rendered HTML content directly to the client’s browser.May lead to slower initial load times as the browser needs to execute JavaScript code to render the content, especially for content-rich pages. However, subsequent interactions can be faster due to client-side caching and optimizations.
Dynamic ContentBetter support for dynamic content, as the server can generate HTML dynamically based on user requests and database queries.Requires additional measures such as server-side rendering or pre-rendering to ensure that dynamic content is properly indexed by search engines.
Mobile FriendlinessProvides consistent HTML content across devices, ensuring better mobile friendliness and improved SEO rankings for mobile searches.Requires careful optimization to ensure that mobile rendering is efficient and user-friendly, as mobile-friendliness is a significant factor in mobile search rankings.
JavaScript DependencyLess dependent on JavaScript for content rendering, ensuring that search engines can access and index the content even if JavaScript is disabled.Relies heavily on JavaScript for content rendering, requiring proper handling of JavaScript for SEO optimization and ensuring that search engines can execute and index the content.

Hold on a moment, before you declare your final verdict, you need to read this too.

The truth is, not all websites can efficiently run through Server-Side Rendering (SSR). For highly interactive sites or those requiring real-time updates, SSR can lead to slower performance or issues with functionality. Since search engines also consider user interaction, functionality, and page load speed as ranking factors, it’s crucial to focus on all aspects rather than solely on crawlability.

While SSR has an advantage in initial page load times, subsequent page navigations and interactions within a CSR application can be faster since they don’t require a full page refresh, and only the necessary content is loaded and rendered dynamically on the client-side.

CSR allows for more seamless updates and interactions without requiring full page reloads, making it better suited for dynamic user experiences.

SSR tends to perform better in terms of initial page load times, which can positively impact metrics like Largest Contentful Paint (LCP) and First Contentful Paint (FCP). Since SSR delivers pre-rendered HTML from the server, it often results in faster perceived loading times.

However, CSR can excel in subsequent interactions and dynamic content loading, which can affect metrics like Time to Interactive (TTI) and Total Blocking Time (TBT). CSR enables seamless updates and interactions without full page reloads, leading to a more responsive user experience.

Now that I have clearly elaborated the effect of SSR and CSR on SEO, let’s come to the final conclusion. Is CSR really bad for SEO? Does websites with CSR cannot rank in Search Engines like Google or Bing?

Well, websites with Client-Side Rendering (CSR) can still rank at a better position in search engines, even though the challenges are higher compared to SSR.

How to Make a Client-Side Rendered (CSR) Webpage Rank in Google?

Client-side rendered (CSR) pages can still rank in search engines like Google or Bing, but it requires additional effort and techniques to overcome the challenges posed by CSR.

Here are some strategies that can help CSR pages rank in search engines:

  • Server-Side Rendering (SSR): Implementing server-side rendering for the initial page load can provide search engines with a fully rendered HTML snapshot of the page. This allows search engine crawlers to easily index the content and understand the page structure.
  • Pre-rendering: Pre-rendering involves generating static HTML versions of the CSR pages during the build process or on the server. These pre-rendered pages can be served to search engine crawlers, while the CSR version is served to regular users.
  • Dynamic Rendering: Some platforms, like Puppeteer (a headless Chrome browser), can be used to dynamically render CSR pages on the server when requested by search engine crawlers. This provides the fully rendered HTML to the crawlers.
  • Incremental Static Regeneration (ISR): With ISR, static versions of the pages are generated on the server and updated incrementally based on changes to the data source. This approach can help balance the benefits of static and dynamic rendering.
  • Structured Data and Metadata: Properly implementing structured data (e.g., JSON-LD) and meta tags can help search engines better understand the content and context of CSR pages.
  • Progressive Web Apps (PWAs): PWAs can provide a server-rendered version of the application to search engines while offering a fast and reliable experience to users through service workers and client-side rendering.
  • Lazy Loading: Lazy loading can improve the initial load time of CSR pages by deferring the loading of non-critical resources until they are needed, which can positively impact search rankings.
  • Optimizing JavaScript Execution: Optimizing JavaScript execution by techniques like code splitting, tree shaking, and minification can improve the performance and render times of CSR pages, which is a ranking factor for search engines.
  • Crawl Budget Management: Ensuring that search engine crawlers can efficiently discover and crawl the important pages of a CSR website by managing the crawl budget and providing a sitemap can improve indexing.

When to Choose Server-Side Rendering & Client-Side Rendering (Performance Comparison)?

Choosing between Server-Side Rendering (SSR) and Client-Side Rendering (CSR) depends on various factors, including the specific requirements and goals of your website or application.

CriteriaServer-Side Rendering (SSR)Client-Side Rendering (CSR)
SEOBetter indexing and ranking due to pre-rendered HTMLRequires additional effort for SEO optimization
Initial Load TimeFaster initial load timesSlower initial load times, but faster subsequent updates
InteractivityLimited interactivity without additional client-side logicHighly interactive and dynamic user experiences
Server LoadIncreased server load, especially for complex pagesReduced server load, better scalability for large apps
Offline SupportLimited offline support without additional client-side cachingEnhanced offline support through client-side caching
Offline SupportLimited offline support without additional client-side cachingEnhanced offline support through client-side caching
Development FlexibilityLess flexibility, tied to server renderingMore flexibility, easier separation of concerns
Legacy Browser SupportBetter support for older browsersRequires modern browser support for JavaScript execution

Choose Server-Side Rendering (SSR) for better SEO crawlability, faster initial load times, and consistent content across devices. Opt for SSR when search engine visibility and mobile friendliness are priorities. Select Client-Side Rendering (CSR) for highly interactive applications, real-time updates, and reduced server load. CSR offers greater flexibility in development and enhanced offline support. Choose CSR for dynamic user experiences and scalability, especially for large applications with complex client-side logic. Consider hybrid approaches for balancing SEO benefits, digital marketing efforts, and interactivity needs. Ultimately, the choice depends on specific requirements, performance goals, and development considerations.