What is difference between client side rendering (CSR) and server side rendering (SSR) in web development?

Client-side rendering (CSR) and server-side rendering (SSR) are two different approaches to rendering web pages in web development, each with its own advantages and disadvantages. Here's a comparison of the two:

1. Rendering Location:

   • CSR: Rendering primarily occurs in the client's browser using JavaScript. The server sends minimal HTML, CSS, and JavaScript files, and the browser handles rendering and updating the DOM.
   • SSR: Rendering occurs on the server. The server generates the HTML for the web page and sends the fully-formed HTML to the client's browser.

2. Initial Page Load:

   • CSR: Initial page load may be slower because the browser needs to download and execute JavaScript code before rendering the page content.
   • SSR: Initial page load is generally faster since the server sends back fully-rendered HTML, which the browser can display immediately.

3. Subsequent Page Updates:

   • CSR: Subsequent page updates and content changes are handled dynamically by JavaScript running in the browser without full page reloads, resulting in a smoother user experience.
   • SSR: Subsequent page updates may require additional requests to the server, which can result in slower perceived performance compared to CSR.

4. SEO (Search Engine Optimization):

   • CSR: SEO can be challenging because search engine crawlers may have difficulty indexing content that is rendered client-side, especially if it relies heavily on JavaScript for content generation.
   • SSR: SSR is more SEO-friendly because the server sends fully-formed HTML to the browser, making it easier for search engine crawlers to index content.

5. Server Load:

   • CSR: The server primarily serves static files and handles API requests, resulting in reduced server-side processing and bandwidth usage.
   • SSR: The server needs to render pages for each request, which may result in higher resource usage compared to serving static files.

6. Complexity:

   • CSR: Implementing CSR can be simpler since most of the rendering logic resides in client-side JavaScript.
   • SSR: Implementing SSR may add complexity to the server-side codebase, especially for applications with dynamic content and interactions.

In summary, CSR and SSR are two different approaches to web page rendering, each with its own trade-offs in terms of performance, SEO, server load, and complexity. The choice between CSR and SSR depends on factors such as the specific requirements of the application, performance goals, SEO considerations, and the desired level of interactivity and user experience.