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Browser Caching & Page Speed Optimization

Enable Browser Caching for Faster Page Load

By
James Gibbons
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Have you ever clicked on a website only to find yourself waiting for an eternity for the page to load? Frustrating, isn't it? The truth is that slow-loading pages can be detrimental to your user experience and ultimately affect your business's bottom line. A recent study has established that 53% of users abandon a website if it takes longer than 3 seconds to load.

This is where caching comes in handy. You might have heard of the word cache a lot. Deleting cache almost seems to work magic in case of browser errors like pages not loading or images not showing up.

But did you know that caching is also a critical component that can significantly impact page speed? Caching is a method of storing data so that it can be easily accessed the next time it is requested. It's like having your personal assistant who remembers your preferences and is always ready to serve you without delay.

In this blog, we'll dive into the world of caching and explore how it works to improve the performance of websites. So keep reading to learn how caching can transform your website's page speed.

What is Caching?

Caching is a technique used in web development and networking to improve the performance and efficiency of data retrieval. It involves temporarily storing a copy of frequently accessed data, such as images, scripts, and stylesheets, either on the client-side (browser cache) or server-side (proxy cache) in a cache, which is a temporary storage location. When a user requests the data, it is retrieved from the cache instead of the source, resulting in faster access times and reduced load on the server.

In plain, simple English: Caching is like putting important things you frequently use on a shelf near you, so you can easily access them when needed. Instead of going all the way to a storage room each time you need something, you can grab it quickly from the shelf. This saves you time and effort. In computer terms, caching stores important or frequently accessed data in a faster and more easily accessible location to quickly retrieve it when needed.

The main idea behind caching is to eliminate redundant processing & minimizing the time it takes to access data by reusing previously fetched information.

Caching is used for several reasons:

1. It significantly improves the response time of web pages and applications.

2. Helps alleviate the server burden by serving cached content instead of generating it from scratch for every request.

3. Reduces the data transfer between the server and the client, resulting in optimized bandwidth usage and decreased network congestion.

For example, when a big news story comes out, many people want to read it. This can make it hard for the website to handle everyone trying to access the story. To help with this, the website saves a copy of the story in a cache. When someone tries to read the story again, the website can show them the saved copy instead of generating a new one. This helps the website handle all the traffic without slowing down or breaking.

Benefits of Caching

1. Improved User Experience: With caching, users can access frequently visited web pages and applications faster, which improves their overall experience and satisfaction.

2. Cost Savings: Caching eliminates the need for expensive hardware upgrades or additional servers to handle increased traffic, resulting in business cost savings.

3. Reduced Bandwidth Usage: Caching helps to reduce the amount of data transferred between the server and the client, reducing overall bandwidth usage and network congestion.

4. Increased Scalability: By reducing server load, caching makes it easier for businesses to scale their websites and applications to handle increased traffic without compromising performance.

5. Improved SEO: Faster loading times resulting from caching can improve a website's search engine rankings, leading to increased visibility and traffic.

6. Optimized Performance for Mobile Users: Mobile devices typically have slower internet speeds and less processing power than desktops. Effective caching can greatly enhance the performance of your website for mobile users, providing them with a seamless experience and reducing bounce rates.

7. Real-time Content Updates: By selectively caching static elements that don't require frequent updates, websites can balance ensuring fresh content and optimizing performance. This approach enables websites to deliver the latest information while maintaining fast load times.

Types of Caching

Different types of caching can be implemented on a website, each offering unique benefits depending on the specific use case. Here are the types of caching and their characteristics:

1. Browser Cache: Browsers like Google Chrome save copies of HTML files, JavaScript, and images on your computer's hard drive and use them for sites you regularly visit instead of downloading them from the server each time. It reduces the load on your server and speeds up page load times, improving the overall page experience.

2. Domain Name System (DNS) Cache: A DNS record tells a browser where to find your website. It servers cache records at servers worldwide, so when someone visits your website, the DNS server physically closest to them directs them to your site. Since DNS records cache all around the globe, its changes often take 24 to 48 hours to propagate.

3. Content Delivery Network (CDN): CDN caching involves storing website assets, such as images, CSS files, and JavaScript libraries, on a network of servers worldwide. When users access your site, the CDN delivers content from the server closest to them, reducing latency and improving load times. It is an excellent option for websites with a global audience or high traffic volume.

4. Page Cache: Page caching involves storing entire web pages as static HTML files in the cache. This type of caching is suitable for content that does not change frequently, such as blog posts or product pages. When a user requests a cached page, it is served directly from the cache, eliminating the need for dynamic processing and significantly improving response times.

5. Object Cache: Like page caching, object caching stores pieces of data for operations such as API calls or database queries. By not repeating the same operations, websites can more effectively scale in traffic without using as many server resources. Object caches can vary in size or type and can be used for a wide range of data storage purposes, improving your web application's overall efficiency and speed.

How Browser Caching Works?

When a user visits a website for the first time, the browser downloads the requested resources from the server and stores them in its cache. On subsequent visits to the same website, the browser checks the cache first to see if it has a local copy of the requested resource. If the resource is found and hasn't expired, the browser retrieves it from the cache, saving the time and bandwidth required to fetch it again from the server.

Let's say you frequently visit a website that has a logo at the top of its page. The first time you visit the site, your browser will download the logo from its server and store it in your browser cache. The next time you visit the site, your browser will check its cache to see if it has the logo already saved. If it does, it will load the logo from the cache instead of downloading it from the server again, which saves time and improves the site's loading speed.

This caching process can also work for other files, such as style sheets, JavaScript, and images. By caching these files, your browser can quickly load the website without having to download all the files from scratch each time you visit. Overall, browser caching is a helpful feature that can help improve your browsing experience by loading web pages faster.

To use browser caching, servers instruct web browsers through HTTP headers, like "Cache-Control" and "Expires." These headers explain how long a file can be cached and when it must be checked with the server again.

Caching & Website Optimization: Impact on Page Speed & SEO

Caching is an essential part of website optimization as it plays a significant role in improving page speed. In today's world, where websites are becoming more complex and heavy on CSS, caching has become more critical than ever.

CSS-heavy websites tend to have more resource-intensive elements that must be loaded on every request. Caching these resources can improve page load times significantly. On the other hand, HTML websites were less resource-intensive and did not require caching to improve page load times.

Caching also has a significant impact on SEO metrics. Google's search algorithm takes into account website speed as a ranking factor. A slow website can lead to a higher bounce rate, negatively impacting SEO rankings. Therefore, website optimization through caching can improve page speed and SEO rankings. Improved page speed also leads to better crawlability and indexability, ensuring that search engines can efficiently explore and understand your website's content.

How to Set Up Browser Caching for Your Site?

Setting up browser caching for your website is crucial in optimizing its performance for returning visitors. Here is how you can set up browser caching on your site:

1. Identify the Resources to Cache: Determine which resources on your website, such as images, CSS files, and JavaScript files, can benefit from caching. These resources should be static and not frequently updated.

2. Set Cache-Control Headers: Configure cache control headers for the resources you want to cache. These headers communicate caching instructions to visitors' browsers. You can set the "Cache-Control" header with directives like "public" or "private" to specify caching behavior.

3. Specify Expiration Times: Set expiration times for the cached resources using the "max-age" directive in the "Cache-Control" header. It indicates how long the browser should keep the resource in its cache before checking for updates.

4. Implement Entity Tags (ETags): ETags are unique identifiers assigned to each resource version. They help browsers determine if the cached resource has changed. Use ETags in conjunction with cache control headers to optimize caching efficiency.

Cache Policy and How to Choose the Right One

Cache policies define how caching should be applied to specific resources on your site. They determine expiration times, cache validation mechanisms, and caching scope. There are primarily two types of cache policies, including:

1. Location-based cache policy: This type of policy defines caching based on the geographical location of visitors. It allows you to serve cached content from edge locations or content delivery networks (CDNs) closer to your users, reducing latency and improving performance.

2. Time-based cache policy: Time-based cache policies set expiration times for cached resources. By specifying how long a resource should remain in the cache before being considered stale, you can balance between caching efficiency and ensuring visitors receive the most up-to-date content.

Cache policies are typically specified using classes such as "Cache-Control," "Expires," and "ETag." These classes provide directives and parameters to define caching behavior, expiration times, and cache validation mechanisms.

When choosing the right cache policy, consider factors such as the frequency of content updates, the sensitivity of the data, and the desired balance between performance and freshness. Evaluate your specific caching needs and consult the documentation of your web server or content management system for guidance on configuring cache policies effectively.

How to Check if Browser Caching is Enabled

To check if browser caching is enabled for your site, you can follow these steps:

1. Open your web browser and navigate to your site or the page you want to test for browser caching.

2. Right-click on the page and select 'Inspect' to open the browser's Developer Tools.

3. Click on the 'Network' tab in the Developer Tools window.

4. Reload the page while keeping the Developer Tools open to see a list of resources being fetched by the browser.

5. Click on a resource from the list, such as an image or script file, and examine the 'Headers' tab in the resource detail pane to find cache-related information. Look for headers such as 'Cache-Control' and 'Expires,' which indicate the cache policy in place.

6. If the headers denote proper caching directives, then browser caching is enabled for that resource.

Common Cache Errors and Solutions

Caching is generally a reliable and efficient technique for improving website performance. However, there are specific scenarios where caching can cause issues, particularly when dealing with dynamic content that changes frequently. Here is why caching sometimes seems to break things and discuss potential solutions:

Why Does Caching Seem to Break Stuff?

Caching works seamlessly for web pages with static content, such as text, images, and videos. However, modern websites often incorporate dynamic features that personalize the content based on user preferences, location, or real-time updates. These dynamic elements pose challenges when caching is involved.

Take the example of an e-commerce website showing personalized product recommendations based on your browsing and purchase history. If this website is cached, it may show you products you've already seen or purchased before instead of updating the recommendations with new products that may interest you.

Furthermore, caching can also cause issues when websites rely on real-time data updates. For instance, a stock trading website that displays real-time stock prices may show outdated information if the website content is cached. This can seriously affect traders relying on up-to-date information to make informed decisions.

The issue arises because caching involves storing a copy of a webpage, which reduces server load by serving the cached version instead of generating the page from scratch. Dynamic features are built using PHP (hypertext processor), JavaScript, or other server-side languages that generate the content on-the-fly and personalize it for each user. When a cached version of the webpage is served, these server-side scripts are not executed, and the personalized content isn't updated. This can result in a suboptimal user experience and lead to confusion and frustration.

To address these challenges, web developers can implement cache-busting techniques. It involves adding a unique identifier to the URLs of dynamic elements, such as product recommendations or real-time data, so that each time a user requests the webpage, the server generates a new version of the content, rather than serving the cached version.

Another approach is to use a cache-control header that instructs the browser or proxy server to store the cached version for a specific duration, after which it must be revalidated with the server to ensure the content is still up-to-date.

Caching and Lighthouse Error: What It Means and How to Fix It

Lighthouse is a performance analysis tool developed by Google that helps website owners evaluate their site's speed, performance, and accessibility. It collects data on various performance metrics, including caching behavior, and analyzes how the browser caches resources like HTML, CSS, JavaScript, and images.

One common Lighthouse error related to caching is the "Serve static assets with an efficient cache policy" error. This error occurs when website assets are not cached efficiently, leading to longer loading times and decreased performance.

To fix this error, developers can implement caching headers in their website's server settings. These headers can control how long assets are cached and when they should be revalidated, improving website performance and reducing server load.

Another common Lighthouse error related to caching is the " Fix assets with an efficient cache policy". This error occurs when the website's assets are not cached efficiently or optimized for quick loading times. To fix this error, developers can use lazy loading, compressing images, and reducing the size of CSS and JavaScript files.

Page Speed Insights Cache Error: Identifying and Resolving the Issue

Page Speed Insights is a tool used to analyze a website's performance by measuring its loading speed and identifying issues that can be addressed to optimize its overall performance. Caching is an essential component of website optimization that improves the page loading speed by storing frequently accessed data on the user's device.

Two common caching errors that Page Speed Insights reports are:

1. Leverage browser caching warning: Indicating that the website is not leveraging browser caching effectively can result in slower page loading times for users.

2. Serve static assets with an efficient cache policy: Similar to Lighthouse & it highlights that static content may not be cached correctly.

These errors can be resolved by implementing proper cache-control headers, setting longer resource expiration times, and utilizing browser and server caching mechanisms. Websites can improve page load times, reduce bandwidth usage, and enhance the user experience by optimizing caching settings.

Best Practices for Caching & Page Speed Optimization

Implementing the right caching and page speed optimization practices can significantly improve your website's performance and enhance user satisfaction. Here are the best practices you should consider:

1. Implement Lazy Loading

Lazy loading delays the loading of non-critical elements such as images, videos, and scripts until they are visible to the user. This technique reduces initial load time, improves perceived performance, and conserves bandwidth. To implement lazy loading, use JavaScript libraries or frameworks like Intersection Observer API to load resources dynamically as they enter the viewport.

2. Optimize Images and Media Assets

Optimizing images and media assets helps reduce file size without sacrificing visual quality. Compress images using lossless or lossy compression algorithms and consider using next-generation image formats like WebP. Leveraging responsive image techniques allows you to serve appropriately sized images based on the device's screen resolution, reducing unnecessary data transfer and improving loading speed.

3. Optimize Resource Delivery

Efficient resource delivery is crucial for optimal page speed. Minify HTML, CSS, and JavaScript files by removing unnecessary characters, whitespace, and comments. Concatenate multiple files into a single file to reduce the number of HTTP requests. Gzip compression further reduces file sizes, allowing for faster data transfer. Use a content delivery network (CDN) to distribute your website's static resources across geographically distributed servers, ensuring faster delivery to users worldwide.

4. Enable HTTP/2 and Server Push

Enabling HTTP/2, the latest HTTP protocol version, allows faster and more efficient communication between browsers and servers. It supports multiplexing, header compression, and server push. Server push proactively sends resources to the client before they are requested, reducing latency and improving page loading speed. Configure your server to utilize HTTP/2 and take advantage of server push to deliver critical assets proactively.

5. Enable Browser Caching for Third-Party Resources

Leverage browser caching for third-party resources to reduce the number of requests made to external servers. Configure appropriate cache headers to instruct the browser to store these resources locally, allowing subsequent page loads to retrieve them from the user's cache rather than making additional requests. It reduces latency and minimizes external dependencies, resulting in faster page rendering.

Implement Caching Correctly for Faster Page Speed

In conclusion, caching and page speed optimization are critical for achieving better SEO performance. It cannot be overstated how much of an impact this can have on your website's overall ranking and success.

Understanding and implementing proper caching techniques can significantly boost your page speed, enhancing user experience and improving search engine rankings. Following best practices and ensuring your caching is set up correctly is essential. Fortunately, the caching process is relatively easy and can significantly impact your website's performance.

Free tools like Google Page Speed Insights & Lighthouse can help you identify common cache implementation errors. However, these reports are generated on a page-per-page level. If you have a big site with thousands of URLs, identifying errors & fixing them needs to happen at scale and faster.

One powerful tool that can help you maximize your site's performance is Quattr. The Quattr SEO platform offers a prioritized list of performance metrics that need your attention & combines errors relevant to the multiple valuable URLs. Quattr helps you identify and fix cache implementation errors across your website, saving you time and effort. It also provides actionable insights and recommendations to help you further optimize your website's performance and improve your SEO rankings.

This valuable information allows you to prioritize and tackle the most crucial caching errors based on their severity and impact on your business. This leads to better user satisfaction, higher search engine rankings, and improved online presence.

Utilize Caching Best Practices & Improve Page Speed at Scale with Quattr!

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Caching for Page Speed FAQs

How do content delivery networks (CDNs) affect browser caching?

Content delivery networks (CDNs) significantly impact browser caching by caching static website content in multiple server locations worldwide, reducing latency and improving response times. CDNs optimize caching policies, employ edge caching techniques, and enable cache purging to enhance content delivery and ensure users receive the most relevant and up-to-date content.

What happens when you don't cache or cancel caching?

When you don't cache or cancel caching, each request for a web page or resource requires a fresh server response, leading to increased server load, longer load times, and higher bandwidth consumption. Content delivery is less efficient without caching, resulting in a diminished user experience, slower page speeds, and potentially higher infrastructure costs due to increased server resources required to handle the load.

What is the difference between server caching and browser caching?

Server and browser caching are two distinct mechanisms vital for website optimization and faster page loads. They differ in where data is stored: server caching uses the hosting server, while browser caching utilizes the user's device.

Should you implement a separate cache policy for mobile websites?

Implementing a separate cache policy for mobile websites can be beneficial due to mobile devices' unique characteristics and constraints. Mobile users often have limited bandwidth and slower connections, making optimized caching crucial for faster page loads. Additionally, mobile websites may have different content requirements and user behaviors, warranting tailored cache strategies to enhance performance and user experience on mobile devices.

About The Author

James Gibbons

James Gibbons is the Senior Customer Success Manager at Quattr. He has 10 years of experience in SEO and has worked with multiple agencies, brands, and B2B companies. He has helped clients scale organic and paid search presence to find hidden growth opportunities. James writes about all aspects of SEO: on-page, off-page, and technical SEO.

About Quattr

Quattr is an innovative and fast-growing venture-backed company based in Palo Alto, California USA. We are a Delaware corporation that has raised over $7M in venture capital. Quattr's AI-first platform evaluates like search engines to find opportunities across content, experience, and discoverability. A team of growth concierge analyze your data and recommends the top improvements to make for faster organic traffic growth. Growth-driven brands trust Quattr and are seeing sustained traffic growth.

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