How to reduce payload sizes.

9 Jul 2024 | 13 min read
How to reduce payload sizes.

Payload size is the total amount of data your website needs to load a page. This includes all the HTML, CSS, JavaScript, images, and other files. When a user visits your website, their browser must download all these files to display the page correctly. The larger these files are, the longer it takes to download them, which can slow down the loading time of your website.

Why Does Payload Size Matter?

The size of the payload matters because it directly affects the speed at which your website loads. If your website has a large payload, it will take longer for users to see the content. This can lead to frustration and cause users to leave your site before it fully loads. A slow website can also hurt your search engine rankings, as search engines like Google prioritize faster sites that provide a better user experience.

How Does Payload Size Affect Core Web Vitals?

Core Web Vitals are three important metrics that measure user experience on your site.

Largest Contentful Paint (LCP) measures how long it takes for the largest element on the page to load. If your payload size is large, it takes longer for this element to appear, making your site feel slow.

First Input Delay (FID) measures the time it takes for your site to respond to the first user interaction, like clicking a button. A large payload can delay this response because the browser is busy loading and processing all the data.

Cumulative Layout Shift (CLS) measures how much the content moves around while the page is loading. Large payloads can cause more layout shifts, making the page look unstable and hard to read.


Imagine you are moving into a new house. If you have many heavy boxes, it takes more time and effort to move them all inside. Similarly, if your website has many large files, it takes more time to load them all. By keeping your payload size small, your website can load faster and provide a better experience for your users. This helps improve your Core Web Vitals and makes your site more enjoyable to visit.

Image Optimization

Optimizing images is crucial because large images can slow down your website. When images are too big, they take longer to load, making users wait. This can lead to frustration and cause users to leave your site. By optimizing images, you can reduce their file size, making your site load faster and providing a better experience for visitors.

Use Modern Formats

Modern image formats like WebP and AVIF are better than older formats like JPEG and PNG. These new formats compress images more efficiently, which means they reduce the file size without losing quality. By using WebP or AVIF, you can make your images smaller and your site faster, improving the overall performance.

Resize Images

Resizing images means making sure they are not larger than necessary. For example, if your website only needs an image to be 800 pixels wide, you should not use an image that is 2000 pixels wide. Large images that are not resized take up more space and slow down your site. Always resize images to the exact dimensions needed for your website.

Compress Images

Compressing images reduces their file size without significantly affecting their quality. You can use tools like ImageOptim or TinyPNG to compress your images. These tools work by removing unnecessary data from the images, making them smaller and quicker to load. This helps improve your website’s speed and user experience.

Use Responsive Images

Responsive images change size based on the device being used. This means that smaller images are loaded on phones, while larger images are used for desktops. You can implement this by using the srcset attribute in your image tags. This ensures that users only download the image size they need, which speeds up the loading time on all devices.

By optimizing your images through these methods, you can significantly improve your website’s performance. Faster loading times lead to better user experiences, which can help increase the time users spend on your site and improve your search engine rankings.

Minifying and Optimizing CSS and JavaScript

Minification is the process of removing unnecessary characters from CSS and JavaScript files without changing their functionality. These characters include spaces, comments, and line breaks. By minifying your code, you reduce the file size, which helps your website load faster. Tools like UglifyJS for JavaScript and CSSNano for CSS can automatically minify your files, making them smaller and quicker to download.

Tree Shaking

Tree shaking is a technique used to remove unused code from your JavaScript files. When you write code, especially with libraries and frameworks, not all of it may be needed for your website to function. Tree shaking helps eliminate this unnecessary code, reducing the file size and improving load times. This is particularly useful when using modular JavaScript bundlers like Webpack, which can automatically perform tree shaking during the build process.

Code Splitting

Code splitting is the practice of breaking down your JavaScript files into smaller chunks that can be loaded on demand. Instead of loading a large JavaScript file all at once, code splitting allows you to load only the parts needed for the current page or feature. This reduces the initial load time and makes your site more responsive. Modern bundlers like Webpack and Rollup support code splitting, helping you optimize your JavaScript delivery.

Bundling and Caching

Bundling is the process of combining multiple CSS and JavaScript files into one file for each type. This reduces the number of HTTP requests your browser needs to make, speeding up the page load time. After bundling, setting up proper caching mechanisms ensures that users do not have to download the same files repeatedly. By configuring your server to cache these files, you can significantly reduce load times for returning visitors.

By minifying and optimizing your CSS and JavaScript, you can reduce the payload size of your website. This leads to faster loading times and a better user experience. Implementing these techniques helps improve your Core Web Vitals, making your website more efficient and enjoyable for users.

Using Content Delivery Networks (CDNs)

A Content Delivery Network (CDN) is a network of servers distributed across different locations worldwide. These servers store copies of your website’s static files, such as images, CSS, and JavaScript. When a user visits your website, the CDN delivers these files from the server closest to the user. This reduces the distance data has to travel, making your website load faster.

Benefits of CDNs

CDNs offer several benefits for your website’s performance. The main advantage is speed. By serving content from a nearby server, CDNs reduce latency and improve load times. This is especially important for users who are far from your main server. Additionally, CDNs help handle traffic spikes by distributing the load across multiple servers, preventing your website from slowing down or crashing during high traffic periods. They also provide better security by protecting your site from Distributed Denial of Service (DDoS) attacks.

Choosing a CDN

When selecting a CDN, consider factors like coverage, performance, and cost. Look for a CDN with servers in locations where most of your users are based. This ensures optimal performance. Check the CDN’s track record for speed and reliability. Some popular CDN providers include Cloudflare, Akamai, and Amazon CloudFront. Evaluate their features and pricing to find the best fit for your needs.

Using a CDN is a straightforward and effective way to improve your website’s performance. By delivering content from the nearest server, CDNs help reduce load times, enhance user experience, and boost your site’s reliability and security. Implementing a CDN can make a significant difference in how quickly and smoothly your website operates.

Optimizing Fonts

Here’s the optimizing fonts

Font Subsetting

Font subsetting involves including only the characters you need in your web fonts. Most font files come with a wide range of characters and symbols, many of which you may not use on your website. By creating a subset of the font that contains only the necessary characters, you can significantly reduce the file size. This makes your website load faster because the browser has fewer characters to download and render.

Font Compression

Font compression reduces the size of your font files without sacrificing quality. Using the WOFF2 format is an effective way to achieve this. WOFF2 is a modern font format that provides better compression than older formats like TTF or OTF. By compressing your fonts, you decrease the amount of data that needs to be transferred, speeding up your website’s loading time.

Loading Fonts Efficiently

Efficiently loading fonts means using techniques that ensure fonts do not delay the rendering of your page. One method is to use the font-display property in your CSS. The font-display property allows you to control how fonts are displayed while they are loading. For example, font-display: swap; ensures that the text is displayed using a fallback font until the custom font is fully loaded. This prevents the user from seeing a blank space where the text should be, improving the perceived performance of your site.

By optimizing your fonts through subsetting, compression, and efficient loading techniques, you can make your website faster and more user-friendly. These optimizations reduce the amount of data the browser needs to download and render, resulting in quicker load times and a better overall experience for your visitors. Implementing these simple strategies can have a significant positive impact on your site’s performance.

Implementing Lazy Loading

Here’s the implementation of lazy loading.

Lazy Loading Images and Videos

Lazy loading is a technique that delays the loading of images and videos until they are needed. Instead of loading all media files when the page first loads, lazy loading only loads these files as the user scrolls down the page and they come into view. This reduces the initial load time, making your website faster and more responsive. To implement lazy loading for images and videos, you can use the loading=”lazy” attribute in your HTML. For example, <img src=”image.jpg” loading=”lazy” alt=”Example Image”> will ensure the image only loads when it is about to appear in the viewport.

Lazy Loading Scripts

Lazy loading can also apply to JavaScript files. By deferring or asynchronously loading non-critical JavaScript, you prevent these scripts from blocking the rendering of the page. The async and defer attributes in the <script> tag can help achieve this. The async attribute loads the script while the HTML is still parsing and executes it as soon as it is available. The defer attribute, on the other hand, ensures that the script is executed only after the HTML is fully parsed. Using these attributes allows the main content of your page to load faster, improving the overall user experience.


Imagine you are at a buffet. If all the food is served at once, it can be overwhelming and slow down the process of getting what you want. But if the food is brought out gradually, as you need it, the experience is smoother and quicker. Similarly, lazy loading ensures that your website only loads what is necessary at the moment, making the page load faster and providing a better experience for your visitors.

By implementing lazy loading for images, videos, and scripts, you can significantly enhance your website’s performance. This technique reduces the initial load time and ensures that users can access your content quickly and smoothly. Lazy loading is an effective and easy way to improve the speed and efficiency of your website.

Removing Unnecessary Plugins and Libraries

Regularly auditing your website for unnecessary plugins and libraries is crucial for maintaining optimal performance. Over time, you may add various plugins and libraries to enhance functionality or design. However, not all of them remain useful. Conduct a thorough review of all the plugins and libraries on your site. Identify those that are outdated, redundant, or no longer serving a vital purpose. Removing these unnecessary components reduces the overall size of your website, which can significantly improve loading times and reduce potential security risks.

Impact on Performance

Unnecessary plugins and libraries can slow down your website. Each plugin or library you add increases the amount of data your site needs to load. This can lead to longer loading times and a poorer user experience. By removing what you don’t need, you streamline your website’s codebase, making it leaner and faster. This directly contributes to better performance metrics, such as faster page loads and improved Core Web Vitals scores.

Alternatives and Replacements

Sometimes, you might need the functionality provided by a plugin or library, but the one you’re using is too bulky or inefficient. In such cases, look for lightweight alternatives that offer similar features without the bloat. For instance, if you use a heavy slider plugin, you could replace it with a more efficient one that offers the same functionality but with a smaller footprint. Research and test alternatives to ensure they meet your needs without compromising on performance.


Think of your website as a backpack. If you fill it with items you don’t need, it becomes heavy and difficult to carry. By removing unnecessary items, your backpack becomes lighter and easier to manage. Similarly, by removing unnecessary plugins and libraries from your website, you make it faster and more efficient.

By regularly auditing and cleaning up your website, you can ensure it remains fast and responsive. Removing unnecessary plugins and libraries helps streamline your site, reducing load times and improving the overall user experience. This simple maintenance task can have a significant impact on your website’s performance and reliability.

Enabling Compression

Compression reduces the size of your website’s files before they are sent to the user’s browser. This includes HTML, CSS, JavaScript, and image files. By compressing these files, you can significantly decrease the amount of data that needs to be transferred over the internet. This makes your website load faster and improves the overall user experience.

Gzip Compression

Gzip is a widely used compression method that reduces the size of your files by up to 70%. When a user visits your website, the server compresses the files using Gzip before sending them to the browser. The browser then decompresses the files and displays the content. Enabling Gzip compression on your server is usually straightforward and can be done by adding a few lines of code to your server configuration. Most modern browsers and servers support Gzip, making it an effective way to speed up your site.

Brotli Compression

Brotli is a newer compression algorithm that often performs better than Gzip. Developed by Google, Brotli can compress files even more efficiently, leading to smaller file sizes and faster load times. Like Gzip, Brotli is supported by most modern browsers and servers. To enable Brotli, you need to configure your server to use it. Many web hosting providers offer Brotli support, or you can enable it manually through your server settings.

Benefits of Compression

The primary benefit of compression is faster loading times for your website. When files are smaller, they take less time to download, which means users can access your content more quickly. This not only improves user satisfaction but also helps with search engine rankings, as faster sites tend to rank higher. Additionally, using compression reduces bandwidth usage, which can save on hosting costs and make your website more efficient.

By enabling compression on your website, you can significantly enhance its performance. Using methods like Gzip and Brotli, you reduce the size of your files, leading to quicker load times and a better user experience. This simple yet powerful optimization technique is essential for maintaining a fast and responsive website.

Upgrading to HTTP/2

HTTP/2 is the latest version of the Hypertext Transfer Protocol (HTTP), which is the foundation of data communication on the web. It was designed to improve the speed and efficiency of web communications. HTTP/2 introduces several key features that help websites load faster compared to the older HTTP/1.1. It is widely supported by modern browsers and web servers, making it a beneficial upgrade for most websites.

Benefits for Payload Size

One of the main advantages of HTTP/2 is its ability to handle multiple requests simultaneously over a single connection. This is known as multiplexing. In HTTP/1.1, each request and response pair had to wait for the previous one to finish, leading to delays. HTTP/2 eliminates this bottleneck by allowing multiple requests and responses to be sent and received at the same time. This reduces the time it takes to load all the elements of a webpage, especially those with many images, scripts, and stylesheets.

Server Push

HTTP/2 also includes a feature called server push. This allows the server to send resources to the browser before it even asks for them. For example, if the server knows that a webpage requires certain CSS and JavaScript files, it can start sending these files immediately after the HTML, even before the browser requests them. This proactive approach can further reduce load times and improve the user experience.

Simple Example

Think of HTTP/2 like a multi-lane highway compared to HTTP/1.1, which is like a single-lane road. On a single-lane road, cars (data) have to wait in line, causing traffic jams (delays). On a multi-lane highway, many cars can travel side by side, reducing traffic and getting everyone to their destination faster. Similarly, HTTP/2 allows multiple pieces of data to travel simultaneously, speeding up the loading process.

By upgrading to HTTP/2, you can take advantage of these advanced features to make your website faster and more efficient. This upgrade can lead to quicker load times, better performance metrics, and a smoother user experience. Implementing HTTP/2 is a straightforward way to enhance your website’s performance and keep up with modern web standards.

Upgrading your website to HTTP/2 is a simple yet powerful way to improve its speed and efficiency. By leveraging features like multiplexing and server push, you can significantly reduce load times and enhance the user experience. Embracing HTTP/2 ensures your website remains fast, responsive, and aligned with modern web standards, ultimately benefiting both your users and your search engine rankings.

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