A content delivery network (CDN) can help boost your site’s performance by using a distributed network of servers to deliver resources to the reader from the server geographically closest to them. It can help reduce server load, speed up delivery, and manage spikes in traffic.
Ideally, you should be using a CDN to serve your entire site.
What is a CDN?
Back in the early days of the internet, when you went to visit a website, your request would be sent from your computer browser to a server which would send back the information to render the page you desired.
The problem was, if there were too many requests coming in simultaneously, the server could max out and crash, preventing that page from loading and making it unresponsive. Website creators had to deal with unreliability, slow loading, and lots of frustration.
CDNs were created to help reduce some of these issues. Using a network of connected servers spread out around the world, a CDN can serve content quickly, reliably, and securely. This simultaneously spreads the strain of loading your website across many servers and uses servers geographically closest to your site visitors.
While a CDN doesn’t replace your host or actually host your website content, it does help serve some or all of the files that make up a page, which can help reduce strain on your host’s bandwidth, prevent interruptions in your site experience, and boost security.
What are the benefits of using a CDN?
CDNs can reduce latency and speed up page loading
CDN servers are usually located closer to your site visitor than your main hosting server, so they have a quicker round-trip time (RTT), reducing latency.
By serving your site’s content via the closest CDN server to your reader’s physical location, they will experience quicker site rendering.
Slow-loading sites can drive readers away, so by improving performance you can boost your traffic, reduce bounce rates, and increase time on page and the number of pages people enjoy on your site.
CDNs can help optimize the elements of your site
From minification to file compressions, CDNs’ additional features can help speed up your site by reducing the amount of data that is exchanged between the browser and the server. CDNs can provide image compression services, minify script, and perform other helpful optimizations that can lead to quicker load times for your reader.
CDNs can provide your site with increased security
Security is more important than ever. There are lots of malicious attacks going on every day, such as Distributed Denial of Service (DDoS) attacks.
In addition to the security provided by your host, CDNs can offer another level of protection for your site against these attacks, through firewalls and other security settings.
CDNs can help manage viral spikes and high-volumes of traffic
When a post goes viral, your CDN can help take the brunt of all the increased traffic. Due to the distributed nature of the CDN’s servers, it can help handle unusual influxes of traffic and minimize the load on your hosting server.
CDNs can be proactive about implementing performance-enhancing features
CDNs can proactively make some optimizations for you such as switching to TLS 1.3 and/or HTTP/3. Check with your CDN to see what improvements they can make for you (or already have)!
Using a CDN can help boost page performance and improve your Core Web Vitals scores
By speeding up your page load times, reducing the weights of the elements on your page, and reducing the need for multiple trips to your origin server, your site can render more quickly for readers, leading to a happy reader and a happy Google.
Best practices for using a CDN
Cache as much content as possible
Caching content to boost performance is one of the primary benefits of a CDN.
Websites consist of a mix of static content and assets (things that generally stay the same, like your website navigation bar) and dynamic content and assets (things that change more frequently, like a gallery of the latest posts on your site). You can cache both types of content, minimizing trips back and forth to retrieve the requested content from the origin server each time.
Most CDNs cache and serve images and a few other static file types by default. To take full advantage of your CDN, you might consider caching everything, including your HTML. This will allow the CDN to serve the full page response to a site visitor from the server closest to them, without anything needing to come from your hosting server, which likely is further away from the visitor than the nearest CDN server.
If you do decide to cache your HTML, just be aware that any updates might not be immediately reflected to site visitors. If the increased site speed is a worthy trade off for you, be sure to clear your cache after making any major changes to your site or individual pages.
Optimize your CDN performance
Enable features such as Brotli, TLS 1.3, HTTP/2, and even HTTP/3 to help further boost performance. A good CDN provider will be able to set up these optimizations for you.
Here are a few things you can ask your CDN to see if you’re set up for the best performance:
- Are all of my site’s text-based responses compressed with Brotli (most preferable) or GZIP?
- Is my site using TLS 1.3 for better privacy and performance?
- Is my site using HTTP/3 (if available — otherwise use HTTP/2) instead of HTTP/1?
- Do you offer CDN image optimization services to help compress my images?
Want some more tips? Check out Google’s helpful guide here to learn more about selecting the right CDN for your site and fine-tuning for maximum performance.
Your Core Web Vitals roadmap
Knowledge is power! Start here:
Dig deeper to understand each metric and why it’s important for user experience:
- What is Largest Contentful Paint (LCP)?
- What is First Input Delay (FID)?
- What is Cumulative Layout Shift (CLS)?
Benchmark your site’s Core Web Vitals so you understand your starting position:
Make a step-by-step plan to improve Core Web Vitals:
- Your four-step playbook for diagnosing and improving Core Web Vitals + a handy one-sheet to go over with your developer or host
Tackle low-hanging fruit:
- How to choose the right hosting service for a speedy site
- 5 tell-tale signs you’ve outgrown your hosting service
- How a good host can help boost page speed and improve Core Web Vitals + a checklist for hosting optimizations
- How switching to a high-quality host can improve Core Web Vitals [Case Study]
- Use a CDN to help speed up your site [You’re here!]
- 23 optimizations to improve your page speed and Core Web Vitals scores