Website performance plays a crucial role in delivering a great user experience. Slow-loading websites can lead to frustrated users, higher bounce rates, and lost opportunities. I’ve written about performance in the past, specifically about diagnosing Sitecore performance problems. Sub 500 millisecond time-to-first byte is hugely important and there are a number of ways to get there, but one of the most effective strategies to optimize website performance is through caching. Caching enables websites to serve content faster, usually from a server much closer to the end user, reducing load times and improving overall user satisfaction. In this blog post, we’ll explore how caching works and delve into the ways it helps enhance website performance. We will also discuss some Sitecore specific considerations.

Understanding Caching

Caching is a mechanism that stores and delivers frequently accessed data, such as web pages, images, stylesheets, and scripts, in a storage location called a cache. When a user visits a website, the browser or server checks the cache first to see if the requested data is already stored there. If it is, the cached version is delivered to the user, eliminating the need to fetch the data from the server. This significantly reduces the time it takes to load the web page and also reduces load on the web server.

Types of Caching

Browser Caching

Browsers store resources like images, stylesheets, and scripts in a local cache on a user’s device. When the user revisits the website, these resources are loaded from the cache, resulting in faster load times. The duration of browser caching is controlled through HTTP headers, ensuring resources are periodically refreshed to stay up-to-date. Out of the box, Sitecore is not optimally configured to properly cache assets in the user’s browser. If possible, the recommendation would be to set the Cache-Control header value to a huge value (max-age=31536000,immutable) along with unique file names (and no versioning for media assets).

Server-Side Caching

Websites can employ server-side caching to store dynamically generated content in a cache. When a user requests a particular piece of content, the server retrieves it from the cache instead of generating it from scratch. This is especially useful for content that doesn’t change frequently, such as blog posts or product descriptions. Sitecore already has a server side caching built in. Sitecore comes out of the box with multiple caching layers (prefetch, data and item as examples) but the most important for non-headless Sitecore solutions is the output cache. Rendered HTML from a component or page is stored in the output cache so that Sitecore simply needs to serve the HTML directly from memory (cache). Properly utilizing output caching in Sitecore will make your website’s time-to-first byte significantly better.

Content Delivery Network (CDN) Caching

CDNs are distributed networks of servers that store cached copies of a website’s static assets. When a user accesses a website, the CDN serves the cached content from a server located closer to the user’s geographical location, reducing latency and improving load times. Out-of-the-box Sitecore doesn’t do a particularly great job with default configuration on media items. Do not version Sitecore media items and apply strong cache settings to aggressively cache media assets at the CDN.

Benefits of Caching for Website Performance

Faster Load Times

Caching significantly reduces the round-trip time needed to fetch resources from the server or external sources. This leads to faster load times and a smoother user experience. Studies show that even a one-second delay in load time can lead to a substantial increase in bounce rates.

Reduced Server Load

Caching reduces the load on web servers by serving cached content instead of generating it for every user request. This scalability is particularly valuable during traffic spikes.

Bandwidth Savings

Caching reduces the amount of data that needs to be transferred between the server and the user’s device. This not only speeds up load times but also helps conserve bandwidth, which is crucial for users on slower connections or limited data plans.

Improved SEO

Website speed is a ranking factor for search engines like Google. Faster-loading websites tend to rank higher in search results, leading to increased organic traffic and better visibility.

Conclusion

Caching is the superhero for website performance optimization. By storing and serving frequently accessed content, caching minimizes load times, reduces server load, and ultimately enhances the user experience. Implementing caching strategies, whether through browser caching, server-side caching, or CDNs, empowers websites to deliver content quickly, resulting in happier users, higher engagement, and improved business outcomes. If you’re aiming to provide a top-notch online experience, harness the power of caching and watch your website soar to new heights of performance.