Website Caching: All You Need to Know About It

Is your website taking a long time to load? Are you struggling with high server loads during spikes in traffic? If so, website caching may be the solution you’re missing.

Effective site caching can dramatically improve your website’s performance, no matter how complex or large its setup is. With a reliable caching solution in tow, you can, in turn, deliver a better user experience (UX) for your customers and improve your search engine rankings as a result.

With that in mind, let’s break down the definition of website caching, how it can be implemented effectively, and recommendations for keeping it in good working order.

What is Website Caching?

Caching refers to a performance optimization technique that stores copies of web page data for future use. The cached data includes the site’s static content like HTML, CSS and JavaScript files, images (in all file formats like JPG, WebP, PNG and more), and other resources that are unlikely to change quickly or often.

When caching is implemented, browsers can display websites without fetching resources directly from the host server in every request. Instead, a cached version can be quickly delivered to users, which is the result of a shorter, more efficient transmission of data. In turn, this improves load times and reduces strain on the host web server.

Benefits of Website Caching

With caching, website owners can witness several advantages:

• Faster page loading speeds
• Eliminating the need for redundant data transfers and processing
• Lowers the required server processing power 
• Servers can handle more traffic without affecting performance
• Reduced bounce rates on sites (the longer pages load, the bounce rate probability increases)
• Higher rankings in search results, leading to increased organic traffic
• Lower bandwidth consumption and costs

How Website Caching Works

During a standard website visit where caching is not present, this is the typical process:

1. A visitor enters a website URL or clicks a link to land on a site.
2. The visitor’s browser sends an HTTP request to the host’s web server.
3. The host server processes the request, often querying databases and executing code.
4. The host server assembles the requested page and sends it back to the visitor’s browser.
5. The browser renders the page for the visitor to view.

This process occurs every time a user visits a page on your site. 

With caching, however, the workflow changes slightly:

1. When a page is first requested, the server processes it normally.
2. A copy of the processed page or the majority of its static components is saved in a cache.
3. When subsequent visitors request the same page, the system can deliver the cached version instead of processing everything again.
4. This bypasses time-consuming database queries and server-side processing.

As a result, the page loads more quickly thanks to fewer resources required.

Types of Website Caching

Website caching processes can be broken down into various other definitions which require some differentiation:

• Browser caching – occurs on the visitor’s device, with their web browser storing local copies of static resources like images, HTML, CSS and JavaScript. On return visits, the browser can access these resources from its local cache directory rather than request them from the host server again.
  
  Implementing browser caching requires a manual server configuration where HTTP cache headers are sent. These essentially tell browsers how long cached resources should be retained for before requesting fresh versions.
  
• Server-side caching – happens on the web hosting infrastructure itself, and can be further broken down.
  • Page caching – saves complete and fully rendered HTML pages. After the first user requests a page, subsequent visitors receive the pre-generated version, nullifying the need to execute PHP or query databases per visit. This is ideal for mostly static pages like blogs or service pages.
  • Object caching – stores the results of API or database queries within the system. Instead of repeatedly delivering these resources, the system can access the cached information. This is particularly handy for complex site setups and eCommerce stores.
  • Fragment caching – saves specific portions of pages rather than them in their entirety. This is useful for predominantly dynamic pages but contain static elements that need lots of resources to generate (e.g. navigation menus, footers, sidebar widgets, etc.)
    
• Content delivery network (CDN) caching – distributes static website content across multiple distributed servers. When a visitor requests a site, a CDN delivers cached content from the server nearest to them, reducing load times and latency. This is handy for websites with global audiences, minimizing the distance data must travel. The CDN market is growing rapidly, predicted to reach a $51.89 billion valuation in the next decade.

How to Implement Caching on Your Website

For WordPress Sites

WordPress offers numerous caching plugins that simplify caching integration, including (but not limited to):

• WP Rocket
• W3 Total Cache
• WP Super Cache

Most of these plugins allow you to enable browser, page, and object caching relatively simply.

For Non-WordPress Sites

Those of you not using WordPress have several caching options, including:

• Varnish, Redis, or Memcached (server-side only)
• Laravel Cache, Django and other framework-specific caching tools
• Cloudflare, Fastly, NitroPack or StackPath, with CDN integrations

Why Clearing Cache is Important

Caching improves and simplifies routine server-browser requests, making it beneficial for both parties. However, it can sometimes prevent visitors from seeing up-to-date content. As such, occasional cache clearing is necessary.

Most caching solutions offer options for:

• Manual cache clearing
• Automatic cache clearing on a per-page basis (e.g. pages that frequently update)

You have the option to set appropriate cache clearance processes based on how frequently your content changes.

How to Implement Caching Effectively

For businesses, successful cache implementation requires a strategic, methodical approach. As a guide, consider the following steps to implement the right caching solution:

1. Assess your website needs and caching requirements. Static websites may not need as comprehensive a caching solution as an eCommerce site, for example.
2. Implement tools to track your site’s performance before and after enabling caching, so you can identify issues and opportunities for improvement.
3. Find the right balance between freshness and speed. In other words, set the right cache lifetime to ensure you can deliver a good UX and performance without depriving users of seeing up-to-date content.
4. Determine how and when cached content should be updated. For example, implement automatic caching on pages that frequently update, schedule periodic purges and manually clear cache on pages that break accidentally. Consider clearing entire caches when sites are patched and updated.

Common Caching Challenges 

• Consider separate cache versions for mobile and desktop sites
• Test cached pages across multiple devices
• Never cache pages containing sensitive user information
• Implement proper cache headers to prevent information leakage or security vulnerabilities
• Regularly patch and update caching plugins and software to secure known issues

Caching is a Valuable Asset to Your Site Performance

Understanding caching’s definition, its processes and best practices for implementation can help site owners leverage it to improve their traffic, UX and performance. It remains a powerful optimization technique that can offer a wealth of benefits both short- and long-term.

Whether you’re running a small portfolio site or an enterprise-level custom web application, caching should be a core component of your performance improvement strategy.

Start with the essentials, monitor the progress and results, and refine your approach from there.