As more and more websites are built using JavaScript frameworks, it’s vital to understand the rendering method’s impact on search engine optimization.

Pages that load in under 2 seconds see a bounce rate of 9%, while pages that take 5 seconds or more to load witness a bounce rate of 38%. Understanding both CSR and SSR regarding SEO is essential to know the best choice for your website.

Client-Side Rendering:

CSR (Client-Side Rendering) refers to rendering a web page on the client side (Client device), typically using JavaScript.

The client’s web browser receives the HTML, CSS, and JavaScript from the server, and then the JavaScript is executed to render the page dynamically.

Source: Growth Rocket

Server-Side Rendering:

SSR (Server-Side Rendering) refers to rendering a web page on the server side and then sending the fully rendered HTML to the client’s web browser.

SSR allows for a faster initial load time, as the browser does not need to wait for JavaScript to execute before displaying the page.

Source: Growth Rocket

Use cases for Client-Side Rendering (CSR)

Here are the primary use cases where CSR is the best for development practices.

Dynamic interactions:

Provide a more seamless and responsive user experience for dynamic interactions, such as form submissions, real-time updates, or user-specific content.

Single-page application:

Faster and more efficient user experience for single-page applications (SPA) by avoiding full-page reloads.

Large amounts of JavaScript:

Handling a lot of complex scripting – it allows the JavaScript to be executed on the client side, reducing the load on the server.

User-specific content:

Display user-specific content, such as personalized recommendations. The client’s browser requests and display the content without involving the server.

Flexibility:

Enable developers to use the latest JavaScript libraries and frameworks, giving them the flexibility to build complex and interactive web applications.

Use cases for Server-Side Rendering

Here are the primary use cases where SSR is the best for development practices.

Search engine optimization (SEO):

Send fully rendered HTML to the search engine crawler, making it easier to index the content.

Performance:

Provide a fast initial load time by sending fully rendered HTML to the client’s browser, allowing it to display the content without waiting for JavaScript to execute.

Static content:

Reduce the load on the client’s browser and allow for faster content rendering which is excellent for static content such as blogs or news websites.

Accessibility:

Support users with slow internet connections or devices with limited processing power. SSR reduces the amount of JavaScript that needs execution on the client side.

Server-side logic:

Reduce load on the client’s browser for user authentication or data processing. Handling these tasks on the server side also increases security.

Advantages of Client-Side Rendering for SEO

Overall loading time:

Users can navigate between your pages without making a roundtrip to the server. Fewer HTTP requests are made to the server since the same assets don’t have to be downloaded again for each page load.

Improved user experience:

Allow for a more dynamic and interactive user experience, which can improve user engagement and time on the site.

Better indexing by search engines:

Search engines can better index dynamic content generated by JavaScript, improving the chances of appearing in search results.

Easier to implement dynamic content:

Implementing is easier for dynamic content, such as user-generated content, product listings, or custom content for different user segments.

Disadvantages of Client-Side Rendering for SEO

Slower initial loading time:

Initial loading time can be slow if the JavaScript is significant. The browser needs to download and execute it before rendering the content. The initial page of the website will take time to load.

Dependence on JavaScript:

Reliance on JavaScript, which may not be supported or enabled on all devices, leads to a degraded or broken user experience for some visitors.

Poor crawlability:

Search engines may need help to crawl and index dynamic content generated by JavaScript, reducing visibility in search results.

Increased complexity:

Requires a more complex development process, including optimization techniques, to ensure that the content is accessible and crawlable by search engines.

Reduced accessibility:

Reduce the accessibility of the site, especially for users with disabilities who rely on assistive technologies that may not be able to interpret the dynamically generated content.

Advantages of Server-Side Rendering for SEO

Initial loading time:

Generates a complete webpage on the server, which is then sent to the client, leading to a faster loading time for the user.

Better crawlability:

Easily crawl and index the HTML generated on the server, leading to improved visibility in search results.

Improved accessibility:

More accessible, especially for users with disabilities who rely on assistive technologies that may not be able to interpret dynamic content generated by JavaScript.

Simplified development process:

Simpler development process, with less focus on optimization techniques, as the HTML is generated on the server and delivered to the client.

Better support for old devices:

Does not rely on JavaScript, making it more compatible with older devices and browsers that may not support modern JavaScript features.

Disadvantages of Server-Side Rendering for SEO:

Slower overall loading time:

Complex applications may lead to a slower overall loading time for the user, as the server generates the HTML for each request.

Increased server load:

Heavier load on the server, as it generates/delivers the HTML for each request, which isn’t feasible for large-scale applications with multiple users.

Lack of dynamic and interactive features:

Doesn’t offer dynamic/interactive features, like real-time updates, user-generated content, or custom content for different user segments.

More complex deployment:

Requires a more complex deployment process. The server must be configured to handle the HTML generation and delivery, which may not be feasible for small-scale or low-budget projects.

Reduced scalability:

Less scalable than client-side rendering since the server generates/delivers the HTML for each request, which can lead to performance impact as the number of users grows.

Overall, it’s important to weigh the pros and cons of server-side rendering and to choose the appropriate approach based on specific requirements.

Tabular comparison for CSR and SSR in terms of SEO:

SEO Metric	CSR	SSR
Initial Loading Time	Good	Poor
Overall Loading Time	Poor	Good
User Experience (UX)	Good	Poor
Dynamic Features	Good	Poor
Interactive Features	Good	Poor
Scalability	Good	Poor
Server Deployment	Simple	Complex
Load on Server	Less	More
Accessibility to Search Engines	Poor	Good
Crawlability	Poor	Good
Supporting all Devices	Poor	Good
Development Process	Complex	Simple

Overall comparison between CSR and SSR

Feature	CSR (Client-side Rendering)	SSR (Server-side Rendering)
SEO	Poor	Good
Performance	Fast	Slow
Development, Complexity	Simple	Complex
JavaScript Support	Required	Not required

SEO:

SSR is the better approach for SEO as search engines can crawl the HTML content of the page more quickly.

Performance:

CSR is generally faster since JavaScript is executed on the client’s browser.

Development complexity:

SSR is generally more complex to implement and maintain.

JavaScript support:

CSR requires JavaScript to be enabled on the client’s browser. SSR does not have this requirement.

In conclusion, there are pros and cons with either one. It really depends on what you’re trying to achieve with your website – factoring in the needs of your end users, your position on accessibility and your SEO strategy. As you develop your website you need to account for those and select the rendering that meets those needs and requirements.