A CDN will massively speed up your entire site and the crucial time to first byte (TTFB) by storing static assets on networks of servers located all over the world, ensuring your visitors get the content loaded in the quickest time possible at the location closest to them, massively improving server lag and response times.
You’re probably familiar with CloudFlare, one of the more popular CDNS options, but there are lots of other options worth checking out.
So let’s go through what’s available and the features to keep an eye out for.
What is a CDN?
The CDN provider copies your static site assets to its servers; the assets are then loaded from the server closest to your site visitors.
It also acts as a load balancer; most CDN providers have networks of servers per location, which means they can easily handle a larger number of requests than if you hosted the files on your own server.
Why Use a CDN?
Using a CDN not only improves your load times but also allows you to handle more visitors to your site at the same time. If your site has ever experienced a sudden and unexpected traffic spike and gone down thanks to being featured on an authority news site in your niche, a CDN could have stopped that from happening.
On top of that, a one second delay can result in a 7% decrease in conversions. Imagine all that money you’re missing out on. Using a CDN, and serving up static assets to your visitors from the servers located closest to them, will help you see a vast improvement in load times and bounce rates.
What to Look for in a CDN
Custom SSL Support
If you already have an SSL-enabled website, you’ll want to make sure that the CDN you pick supports the use of custom SSL without extra charges. CloudFlare forces you onto its business plan to use a Custom SSL, which is $200/month a massive $180/month more than the standard plan.
HTTP/2 is the new web protocol standard. Currently, it only works over SSL and not non-HTTPS websites. Having an HTTP/2 enabled CDN can hugely increase your site’s speed and slash its loading time. Make sure your CDN supports this vital technology.
The more locations a CDN provider has, the greater flexibility you’ll have. You may see this referred to as POPs also known as Points Of Presence. Make sure your CDN provider has locations/POPs covering all major continents, America, Australia, Europe (Eastern and Western), Australia, Asia and, ideally, Africa. Most CDNs don’t currently have data center locations in Africa.
What good is a CDN if you can’t see what’s happening? Most CDNs now offer real-time analytics allowing you to see everything that’s happening on your site at a glance.
Real-time purging of content is a vital component to any CDN solution. If your CDN solution doesn’t offer real-time purging visitors to your site will be seeing old outdated content or styling that you may have changed.
Push Or Pull?
CDNs offer two different types of zones: Push and Pull.
A Push Zone requires that you upload your content to your CDN. It’s then distributed from there to edge servers. Most CDN providers support FTP, SFTP, and rSync to upload your files.
A Pull Zone fetches the requested content from your server/hosting and caches the assets on the edge servers of the CDN provider.
In general, CDN providers usually offer both types of zones, but it’s recommended to use a pull zone for most dynamic sites using WordPress, as content often changes whether that be through uploading additional files for a post or page or updating plugin/themes. You wouldn’t want to have to upload it to both your website and the CDN separately.
Rules allow you to set up custom behaviors for how your content should be handled or if files should be excluded. If your CDN doesn’t enable you to control what is and isn’t served via its network, don’t use it. WordPress plugins can sometimes break when their files are served via a CDN or if the CDN offers minification solutions. Always make sure your CDN allows you to exclude any files you want.
Some CDNs offer additional services for video hosting, ad delivery, software distribution and app delivery.
Support & Service Level Agreement
Before signing up that a CDN, check that it offers a level of support that you feel comfortable with. Many now offer live chat in addition to support tickets, and often enterprise customers get one-to-one live phone support.
Also, check the SLA – you want to make sure that if the network goes down, you’ll be credited for the lost network availability.
Some CDNs charge per GB of traffic, and some on a flat monthly basis with no bandwidth costs. Costs can also vary widely depending on how many zones you set up and what features you want to take advantage of.
At the time of writing, there are no Multisite CDN solutions. While you can use a plugin such as WP Super Cache on a per site basis and manually configure the CDN, there’s no way to set up a CDN solution to automatically configure required records both at the DNS provider and the CDN provider. Other hazards to a network admin include domain mapping, which will also require manual setup to work with your CDN.