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Ashok Naik
Ashok Naik

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The Ultimate Guide to Web Rendering: Improving Performance with CSR, SSR, SSG, and ISR


The process of web rendering, which controls how users see the content of your online application, is essential to web development. Knowing the subtleties of web rendering as a full-stack developer with a focus on the MERN stack (MongoDB, Express.js, React, Node.js) will greatly improve the functionality and user experience of your projects. Key ideas and methods in web rendering are covered in this article, including incremental static regeneration (ISR), server-side rendering (SSR), client-side rendering (CSR), and static site generation (SSG).

Client-Side rendering (CSR)

JavaScript is used to render content in the browser via a method known as client-side rendering, or CSR. In a MERN stack application, CSR is usually handled via React.
This is how it operates:
First Load: The server transmits a small HTML file and a collection of JavaScript files to a visitor that visits your website.
JavaScript Execution: To show the content, the browser first downloads and runs the JavaScript, which then creates the HTML and dynamically modifies the DOM.
User Interactions: The application seems quick and responsive since React manages future interactions on the client-side.
Rich Interactivity: Rich interactivity and quick updates are made possible by React's virtual DOM.
Decreased Server Load: Reducing server load to the client is advantageous for scalability.

Server-Side Rendering (SSR)

Server-side rendering (SSR) is the process of rendering HTML on a server and transmitting it to the client after completion. This can be accomplished in a MERN application utilising frameworks such as Next.js or by utilising React's server-side capabilities. This is how SSR works:

When a user requests a page, the server generates HTML using React components.
Full HTML Response: The server returns fully rendered HTML to the client.
Hydration: Once the HTML is loaded, React takes control, and the application works normally from then on.

Faster initial load: Because the server provides fully rendered HTML, viewers can view the information more quickly.
Better SEO: Search engines may quickly index pre-rendered HTML, which improves SEO.

Static Site Generation (SSG)

Static Site Generation (SSG) pre-renders HTML during the build process. This strategy is useful for pages that do not need to be updated frequently. SSG is facilitated by MERN stack frameworks such as Next.js. This is how it works.

Build Time: During the build process, HTML is created for each page using your React components and data.
Static Files: The server serves these static HTML files with each request, resulting in rapid load times and low server load.


Performance: Pages load extremely fast since they are pre-rendered and serve as static files.
Scalability: Reduced server load as pages are served from a CDN or static hosting service.
SEO: Fully pre-rendered HTML is easily indexed by search engines.

Incremental Static Regeneration (ISR)

Incremental Static Regeneration (ISR) is a new technique that combines the advantages of SSG with the ability to update static material without a complete rebuild. ISR, which is supported by frameworks such as Next.js, lets you update static pages after they've been built. This is how it works.

Pages are pre-rendered during the first build process, similar to SSG.
On-Demand Updates: When a page is browsed, any outdated material is re-rendered in the background and updated.

Fresh material: Pages can be modified without requiring a full rebuild, resulting in fresh material.
Performance: Serves static files, retaining the performance benefits of SSG.
Flexibility: Strikes a balance between static creation and dynamic content updates.

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