How does a CDN improve load time?

Site speed and reliability are critical to keeping your customers happy and driving sales. 9 out of 10 customers will give up on a site if it takes too long to load. Even a split second of delayed load time can result in lost customers - and revenue. 

 A Content Delivery Network (CDN) improves load time by addressing both of these issues: by caching and serving your website's files from local servers, a CDN can dramatically improve your site’s load time. 

What Is a CDN?

A Content Delivery Network (CDN) is a system of distributed servers that deliver web content and pages to users based on their geographic locations to improve performance and reduce latency. A CDN caches and stores your website's essential files, such as HTML pages, JavaScript files, CSS files, images, and videos, on edge servers, resulting in shorter load times.

How Does a CDN Work?

A CDN works by distributing your website's content across a global network of edge servers to route users to the closest edge server for faster load times. 

Here is how a CDN works: 

Content Distribution: A CDN stores copies of your website files on edge servers around the world, helping speed up content delivery and minimizing load delays.

Edge Servers: Your business' content is cached on these strategically positioned servers. Customers accessing your site are routed to the edge server with the lowest latency, typically the server that is physically closest to them.

Load Balancing: CDNs employ sophisticated algorithms to monitor and load balance traffic across the edge server network. More optimal routing decisions and greater resilience mean no single server has to carry too high a load, maintaining optimal performance even as website usage rises.

Data Retrieval: When an end user requests access to your site, the nearest edge server delivers it directly to them without having to retrieve it from your origin server. 

Content Purging and Updating: CDNs also constantly purge, or remove and update, content. This ensures that users always receive the most up-to-date content without companies having to worry about serving outdated information.

How CDNs improve load time

Using the process described above, CDNs can dramatically decrease your website’s load time through several key capabilities:

Reduced latency: An effective CDN minimizes the delay between a data request and the delivery by caching and storing your website's content on servers close to your customers, which means less waiting time.

Enhanced performance:  With content served from local edge servers, your customers will spend less time waiting for pages and assets to load, including those with high-bandwidth, media-rich content, leading to higher satisfaction levels thanks to the smoother user experience.

Increased scalability: During busy periods like Black Friday sales or new product launches, a CDN easily scales to handle unusually large traffic surges to your site. This on-demand scalability allows companies to normalize their server spend and avoid paying for wasted storage during off-peak times.

Improved availability: CDNs allow websites and apps to be "always on", avoiding error messages frustrating your end users. If an origin server goes down, the CDN can continue serving whatever content was last in cache to users from geographically and strategically distributed points of presence (POPs).

Added Bonus: Better SEO. Google uses a set of three key metrics to determine the ‘usability’ of your website, called Core Web Vitals (CWV). CWV considers the loading performance of the website (or webpage), its interactivity and its visual stability. If you are ranking poorly for these metrics, you will be lower in the results. 

How Fastly’s CDN helps improve load time (better)

Sure, all CDNs provide some level of performance enhancing capabilities - they help you to reduce latency by delivering content from a location closer to your user and improve load times. But does the CDN truly offer the most comprehensive set of features to deliver on this promise?

Fastly’s key benefits include:

Global Edge Network: With 291 Tbps of global edge capacity, Fastly’s CDN ensures swift and reliable content delivery, minimizing delays and optimizing user load times worldwide​.

Efficient Caching: Fastly offers, on average, 150ms cache invalidation globally, allowing for speedy updates and ensuring end users receive the most current content without delay​.

Quick Deployment and High Accuracy: Security solutions like WAF can be deployed in minutes and offer 90% effectiveness in blocking malicious traffic with minimal false positives​.

Instant Log Data:  Fastly delivers 100% of log data in real-time, allowing you to gain immediate insights for monitoring and troubleshooting​​.

Elastic Scaling:  Fastly also supports automatic scaling without capacity constraints, making it ideal for businesses enjoying rapid growth or need to deal with variable traffic patterns​​.

Vendor Consolidation:  Fastly’s unified platform consolidates multiple services (like CDN, security, and compute), offering cost savings and simpler admin by reducing the need for multiple vendors​.

High Customer Satisfaction: Fastly consistently achieves high customer satisfaction scores (98% CSAT) and offers lightning-fast response times (10 minutes for enterprise response) with effective issue resolution​.

You can learn more about why site speed is so important, or dig into what makes Fastly the best choice for your CDN needs.