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How to improve page load speed and response times: A comprehensive guide

This post was originally published on Hackmamba.

Users' patience has grown thinner, and they tend to leave websites that take too long to load. Whenever a user clicks a link, they expect a website to load fast enough to keep them interested. Seeing a blank screen or a spinning wheel can be frustrating and discouraging — it ruins the user experience and leads to dropoffs. Thus, ensuring that your website loads and responds quickly is crucial.

This article explores methods to improve page load and server response times. It also discusses their importance and the factors affecting them.

What are page load times?

Page load time (PLT) refers to the time it takes for a web page to load and become fully interactive for the user. It measures how long a webpage will load on your browser after you request a page.

The process of loading a website involves several stages. It begins when you click a link or enter a Uniform Resource Locators (URL) into your browser's address bar. At this stage, you request resources from the server hosting the website you wish to view. Following your request, the server collects data and runs server-side scripts and database queries. Then, the server sends essential files, like images, HTML, CSS, etc., to the user's browser.

Once the browser receives the files, it goes through the rendering stage. The browser interprets code, renders images, etc., and displays the web page at this stage. Finally, the browser displays the content on your screen in the completion stage.

Illustration from Quora

PLT is usually measured in milliseconds or seconds. A fast-loading website creates a positive user experience. Studies have shown that users lose interest quickly in a slow-loading website. According to a 2018 report by Portent, the optimal average page load time is between 0–4 seconds. Thus, if a user clicks the link to your website, it should fully render and become interactive in 0–4 seconds. Note, however, that a page's loading time depends on the device used, file sizes, and more.

Factors influencing PLT

The following factors affect the load speed of a web page:

  • Mobile Devices: Certain limitations can affect mobile page load times for mobile users. These devices typically have smaller screens, slower processors, and less memory than desktop computers. This results in longer page load times, negatively impacting the user experience. As a result, it's important to note that page speed differs on a page's desktop and mobile versions. Thus, mobile websites need to prioritize mobile optimization techniques like code modification. It ensures faster loading times, providing a seamless experience for mobile visitors.

  • File sizes: It takes longer for a larger file to load. Web elements like images, videos, and third-party scripts contribute to the size of a web page. When users attempt to access a website, their device needs to download these files from the server. If the files are large, it will take longer to download, leading to slow page load time. Also, if internet speeds are slow, the files can take ages to reach the users' browsers from the server.

  • Render-blocking resources: Web pages take longer to load when render-blocking resources are present. Examples of these render-blocking resources include fonts, JavaScript, and CSS files. These resources are typically placed in the head section of the HTML document. Thus, a browser must fully load and process them before showing the page's visual elements to the user. A delay in rendering can extend the time it takes for a page to become visible to the user.

Key metrics for measuring PLT and user experience

Measurement of PLT and user experience relies on several key metrics. These metrics help assess how fast users can engage and understand a site's content. Some of the key metrics include:

1. First contentful paint

As soon as you click a link, first contentful paint (FCP) measures the delay until the first bit of content **(text, image) **appears on your screen. It is when the user begins to see meaningful content on the web page, indicating that the page is loading.

The FCP gives users a sneak peek into how fast the page loads. A fast FCP keeps users interested, whereas a slow one can cause annoyance and desertion. The ideal FCP time duration should be under 1.8 seconds.

2. Largest contentful paint

Largest contentful paint (LCP) measures how long it takes for the most significant content (an image or a text) to appear on your screen. It is what you were looking for, and when you see it load up, you know most of the page is ready.

A fast-loading LCP time is essential so users can see the main attraction immediately. It enhances the user experience, while a slow one makes it seem sluggish and incomplete. Also, a fast LCP can boost your website's rankings in search engines since it is a Core Web Vital. Core Web Vitals are user experience metrics Google uses to decide a website's SEO ranking. The ideal duration for LCP should be under 2.5 seconds for optimal website performance.

Largest contentful paint

3. Time to Interactive

Time to interactive (TTI) measures the time it takes for a web page to become interactive and responsive to a user's input. It is when a page loads completely, visually and functionally. The web page is thus ready for users to interact with its elements, click buttons, fill out forms, and more.

Websites with faster TTI provide a more seamless experience for their users. Users are more likely to stay on the website and explore it longer. This results in better user engagement, lower bounce rates, and better conversion rates. The ideal duration for TTI should be under 5 seconds for optimal website performance.

4. Cumulative Layout Shift (CLS)

Cumulative layout shift (CLS) is a web performance metric that measures the visual stability of a web page. It quantifies how much a page's layout shifts unexpectedly during loading. A page web layout shifts when elements, e.g., buttons and images, move between rendered frames. This can happen when images or ads load dynamically, the viewport size changes, etc. When content shifts unexpectedly, it can confuse or cause accidental user clicks.

Over the lifetime of a web page load, CLS acts as a performance metric to calculate all layout shift scores. This results in a single performance score representing the unexpected page layout shifts. A low CLS score (0.1 or less) indicates minimal layout shift, which leads to a smoother user experience. However, a high score (0.25 or higher) shows a more erratic loading experience. Also, CLS is one of Google's Core Web Vitals, along with LCP.

Importance of PLT

Here are the key reasons why prioritizing page load times is crucial:

  • Conversion rates: Conversion rate is a key metric for any website. It is the percentage of visitors to a website who complete a desired action. Depending on the website's goals, it could be a sign-up for a newsletter or a sale to online customers. A fast-loading website increases user engagement and conversion rates.

  • Reduced bounce rates: The speed at which pages load can also impact bounce rates. Bounce rate is the percentage of visitors who leave a website without taking any action. When a site's load time is fast, the bounce rate decreases. It indicates that the site's content is engaging and more attractive to visitors.

  • Search Engine Optimization (SEO): Page loading speed plays a significant SEO role. The faster a page loads, the better it ranks on search engines like Google. The Google algorithm considers page speed to be an important ranking factor. A fast-loading page enhances search engine ranking, improving visibility and organic traffic. Using Google Analytics to track and enhance your website's PLT is also essential.

Techniques to improve PLT

Improving page load times is crucial for better website performance and a better user experience. The following techniques will help speed them up:

1. Image optimization

The majority of what makes a web page large is usually its images. Image optimization ensures the right balance between file size and visual quality. Optimizing images is essential for faster loading times and improved user experience. It is a multifaceted approach that involves considering several techniques:

  • Compressing images: This technique reduces image size without compromising quality. You can achieve this using various image compression tools like TinyPNG or ImageOptim. These tools are specifically designed to manage multiple image formats and compression methods. They help reduce image files, resulting in less data transfer from the server to the user's device. It is advisable to compress images before uploading them to the web server.

  • Image format: Choosing the right image file formats for optimization is vital. Every image format has unique quality characteristics and compression techniques. Thus, it is crucial to understand the features of each format for optimization. For example, JPEGs are ideal for images with complex color variations. PNGs are suitable for images with sharp edges, and SVGs are best for icons and logos. Choose the image format based on the image's content, purpose, and file size.

  • Lazy loading: Lazy loading is a method for improving the speed at which images load on a webpage. All the images on a web page usually load simultaneously, even if the user can't see them immediately. It can cause slower loading times, especially when many big images are on the page. Lazy loading defers the loading of pictures that are not immediately visible on the page to fix this. The browser will handle lazy loading for a picture with the loading= "lazy" HTML attribute.

Note: There are two image compression methods: lossless and lossy. Lossless compression minimizes file size without sacrificing image quality. Lossy compression, in contrast, results in a slight loss of image quality.

2. Use content delivery networks (CDNs)

Content delivery Networks are also called content distribution network (CDN). It plays a vital role in optimizing web page size. CDNs distribute content across geographically dispersed servers, bringing content closer to users. It reduces the latency, or the time data travels from the user's device to the server, and improves page load times.

When a user requests a webpage, the CDN delivers the content from the nearest server to the user. As a result, the loading times are faster since the data has to travel a shorter distance. CDNs offer endless benefits like reduced bandwidth usage, scalability, increased reliability, and more. Some well-known CDNs include Cloudflare, Amazon CloudFront, Akamai, and Fastly. They offer several features that help reduce web page sizes and make websites run better.

3. Asynchronous loading

An asynchronous loading technique enhances page load times by loading certain elements independently. For example, scripts and images can load simultaneously instead of sequentially. Thus, they load in the background while the rest of the page continues to load, creating faster load times.

    <!-- Asynchronous loading of a JavaScript file -->
    <script src="app.js" async></script>
Enter fullscreen mode Exit fullscreen mode

Asynchronous loading of JavaScript files can help prevent page rendering delays. Browsers use the script tags' async attribute to continue rendering while downloading scripts. This asynchronous loading method improves the webpage's overall loading performance and responsiveness. It helps solve common issues associated with synchronous loading, where elements load sequentially. It also aligns with user expectations for faster load times and optimal performance.

4. Minifying and concatenating files

Minification involves removing unnecessary characters, whitespace, and comments from code files. It helps reduce HTML, CSS, JavaScript, etc., file sizes without compromising functionality. Removing redundant elements makes these HTML, JavaScript, and CSS files smaller. Since smaller code files need less internet traffic to transfer, they load faster. Utilizing tools like UglifyJS, Clean-CSS, and HTMLMinifier enhances this process of code reduction. They analyze the code, remove redundant code, and generate optimized files for deployment.

Many web pages use CSS and JavaScript files to handle various features and styles. Each file, however, requires a separate HTTP request, which can slow down page loading. Concatenation comes into play here. It involves combining multiple CSS or JavaScript files into a single file. As a result, pages load faster, reducing the time spent requesting individual files. Gulp, Grunt, and Webpack are some of the tools that can assist you in speeding up the concatenation process. They enable seamless merging of many files during development, ensuring deployment readiness.

What is server response time?

Server response time (SRT) refers to the time it takes a server to respond to a request from a web browser. It is the time the server takes to process this request, create an initial HTML response, and send back the right data to the browser. Fast SRTs improve user experience and website functionality. It helps websites handle high-traffic loads, ensuring uninterrupted browsing and higher conversion rates.

Illustration by SEObility

One key component of server response times is the time to first byte (TTFB). It measures the time from the user's request to receiving the initial data byte. TTFB is typically measured in milliseconds (ms) or seconds (s). Milliseconds are frequently used to quantify fast response times. Using it, you can get more detailed real-time information about quick interactions. In contrast, slow server response times are usually measured in seconds.

When a website's TTFB is less than 200 milliseconds, Google considers it to have a good response time. While 200ms to 1 second response times are acceptable, aiming for faster speeds is best. If it takes any longer than a second, it's an issue. Also, speed is relative: it depends on the server load, hosting service, and lots more. Thus, setting a benchmark and a goal for measuring web response times in a system or application is vital. Establishing these benchmarks makes identifying what forms fast and slow response times easier.

Factors affecting SRT

These are a few of the factors that affect server response times:

  • Network latency: Network latency is the time it takes for data to go from your browser to a server and back. It measures the delay between clicking a link, for example, and receiving a response. When latency is high, it increases the total round trip time (RTT), which means that it takes longer for your request to reach the server and for it to send the first response (SRT). It results in slow page loads and jerky interactions. The user's distance from the server, as well as the type of network connection, can also have an impact on SRTs. High latency can lead to timeouts and errors, which can cause frustration for users.

  • Server load: A web server's load is the amount of processing power and memory it uses at any given time. Server reaction times may be slower than usual when there is a high server load. The server has to process more requests and data, which can lead to overwork and slow response times. Also, if the server runs many services, like a database or an application, it can increase the server load.

  • Hosting service: The hosting service significantly impacts server response time. In this context, it refers to the performance and capabilities of the server that hosts a website. Web hosting providers can cause slow server response times if you choose the wrong one. Thus, choosing the right hosting service is vital if you want your server to be fast and reliable.

Techniques to improve server response times

Here are some techniques to improve server response times:

1. Choose the right hosting service.

Selecting a web hosting service requires considering your website's needs and requirements. Server performance is a crucial factor to keep in mind. A fast and high-performing server will handle requests more efficiently and respond faster. Also, ensuring the hosting service's plan can meet your scalability needs is crucial. It entails determining whether you can expand the CPU, RAM, or storage as your website grows.

Another crucial decision when choosing hosting services is choosing shared or dedicated servers. In shared hosting, many websites use the same server, leading to slower response times. However, dedicated hosting provides exclusive access to server resources, ensuring better performance.

Thus, it is vital to determine how much traffic and resources your website requires. If your website is small and doesn't get much traffic, go with shared hosting. Choose dedicated hosting if your site has many resources (e-commerce website) or has growth potential. That way, you won't have to worry about performance issues in the future. Also, dedicated hosting can be pretty expensive, so your budget will also be a factor in your decision.

2. Implement browser caching

One helpful technique for enhancing server response times is to use browser caching. Browser caching stores static contents, like images and CSS files, locally on a user's device. It reduces the need to download these files each time a user returns to the same website. So, rather than sending the browser to the server again, it retrieves these files from the local cache. Thus, the server does not have to generate the same data constantly, reducing its workload.

Client-side and server-side caching are the two primary categories of caching techniques. Client-side caching involves storing often-accessed web resources like images on the user's device. Browsers can then reuse these locally stored files, reducing repeated server requests. Server-side caching stores content on the server within its memory or storage space. It entails using server-level configurations or caching plugins inside the server software. This method helps to enhance the webpage's loading speed and reduce the server's load.

3. Optimize DNS (Domain Name System) lookups

DNS lookup optimization can reduce network latency, resulting in faster server response times. It translates domain names ( into IP addresses ( that computers can understand. When a user types a domain name into a browser, the DNS system looks up the IP address for that domain name.

DNS caching is one way to optimize DNS lookups. It involves storing DNS lookup results in a local cache. In the future, you can use the cached IP address instead of performing a new DNS lookup for the same domain. This way, a DNS query is no longer needed, reducing the round-trip time and improving response time.

Also, using fast and dependable Domain Name System Servers is vital. A DNS service provider or a CDN with fast and reliable DNS servers can speed up domain name resolution. Since their servers are close to their users, there is less lag and quicker response time.

Tools for performance optimization

Developers use various tools to track page loading and server response times. These tools identify performance bottlenecks and improve the overall performance of your website. Below are some of these tools:

1. Browser developer tools

Browser developer tools are features built into browsers that aid in optimizing performance. These tools are accessible with all popular browsers, like Google Chrome and Firefox. With it, developers can analyze a web page's network requests and responses. They can examine the timing and duration of each request, as well as the response time of the server. Thus, developers can identify potential performance bottlenecks and optimize the loading of resources.

Browser developer tools — performance tab

To access the browser developer tools:

  • Open your browser (Chrome browser) and visit the web page you want to optimize or examine.
  • Right-click on the page and select "inspect" to open developer tools. You can also use the keyboard shortcuts Ctrl+Shift+I (Windows) or CMD + Option + I (Mac).
  • Go to the "Performance" tab in the developer tools panel. This tab provides data about performance timelines.
  • Click the record button or CTRL + E to record the website performance. The record button is usually a circle icon near the top-left corner of the developer tools.
  • Engage with the website to record the sequence of events as the page loads. When you're through, click the stop button to end the recording.
  • Check the performance tab's timeline for any possible bottlenecks and resource-loading delays. Examine the developer tools' suggestions to find and address performance issues.

2. Performance monitoring tools

These tools provide comprehensive insights into frontend performance, user experience, and potential bottlenecks. They measure performance metrics like response times, PLT, FCP, and LCP. Popular performance speed testing tools include Google PageSpeed Insights, WebPageTest, GTmetrix, Pingdom, and Google Lighthouse. They help point out areas of poor performance and send out alerts if response times get too slow.

3. Server-side monitoring tools

These tools track server and underlying infrastructure and backend performance. They monitor several metrics, like disk I/O, CPU and memory usage, network traffic, and more. Some examples of these tools include New Relic, Datadog, and AppDynamics. Web administrators can use them to see what's causing slow SRT, like high CPU usage or network traffic. Server-side monitoring tools also provide real-time alerts to improve server performance.


Delivering a seamless user experience requires optimizing page load times and response times. Implementing optimization techniques like image compression can significantly enhance a website's performance. Also, continuous testing and monitoring are essential to identify areas for improvement. Remember that every second counts regarding retaining site visitors and boosting conversions. Thus, your website's success will increase if you focus on speed and efficiency.


The following resources may also be helpful:

Top comments (2)

fpaghar profile image
Fatemeh Paghar

🚀 Optimizing website performance is more crucial than ever! 💻 Users demand speedy experiences, and slow-loading sites can lead to frustration and drop-offs. 🕐 This insightful article on Hackmamba breaks down the importance of Page Load Times (PLT) and Server Response Times (SRT). 💡

efpage profile image
Eckehard • Edited

Often underestimated is the round trip time (RTT), as this might easily multiply. Assume you store your page setup in a database. Before you can query the setup, you need to perform multiple requests:

  • User inputs an URL
  • Server responds with the initial HTML file
  • Browser find some external libaries, that need to be loaded
  • After all libs are ready, the page can be evaluated
  • Now you can query your database.
  • Response is sent
  • Now you can start to load your final setup

As you might see, this ping-pong game can add a new Round trip on each step it performs.

Image description

Browsers usually use a preload scanner to find external resources. So, they can start to load files before even the page is evaluated (See here or here for more details). Even if you don´t need a file, it might be useful to put a reference in the main HTML file to start preloading it. It might stay in the cache and be ready if you need it later.

It is very important to understand this relations to speed up your pages.