How-to 15 min read

What is a CDN and how to set it up

On average, a visitor needs nearly six seconds to see whether a certain resource appears useful for them or not. Showing all the needed pieces of content with the minimum time spent on loading the page is a task for the CDN — Content Delivery Network.
In order to keep a user on the site and lead them to the target action, we use various optimization methods: eye-catching design, high qualified and useful content, SEO-optimisation, etc. However, quite often we forget about details which eventually play a great role in the site running, influence its ranking and visits.

Website loading speed affects its positions in the list of searching results and influences users' behavior which is also important for ranking and conversion rates. Let's talk about page files loading speed and the CDN — one of the effective ways of the site optimization.

What is a CDN?

Content Delivery Network is a system which helps to increase the files loading speed on the website. It is done due to several servers located at great distances from each other.
How CDN works
CDN acts as a bridge: it connects all the servers into the single net and provides faster content loading. Sometimes it is possible to decrease users' waiting time for 5-6 seconds.

What is a CDN for?

Obviously, nobody enjoys waiting. We don't like staying in a line, waiting for a bus or holding the line until we are connected with somebody. Approximately the same feel users while looking at the screen for 10-15 seconds and expecting for a miracle. However, according to the stats, even 7-10 of waiting are too much. As a result, people simply run out of patience, leave the site, and we lose potential buyers or readers.

The longer images, text, files and other page elements load, the less interest and patience users have. That's why the content loading speed is the most influential factor which positively affects users behavior and the site's reputation in general.

The important role is played by a distance between a server and the user. The longer it is, the more time will be spent until all the data appears on the screen. CDN helps to use and connect several servers which are located to the users as closely as it is possible. This cuts waiting time helps to speed up the page loading for all the users regardless of their locations.

What sites need CDN?

Sites that have a lot of large files definitely need to use the content delivery network. CDN considerably helps to cut the loading time and prevents various data load fails.

Furthermore, for multilingual sites using CDN is strongly advised. Content of such sites is usually translated into at least two languages. Consequently, the server has to load at least two times more info. Users of such sites are scattered worldwide, and most of them are located quite far from the main server.

Due to the CDN, we can create a whole chain of additional servers which are located as close as it is possible to every user which provides more sustainable and quick data delivery and makes the resource accessible for a greater amount of users.

CDN advantages

One of the greatest CND upsides is that it positively influences ranking. Search engines track the user's actions and behavior on the site.

On this basis, the site is considered to be useful for visitors or not. The faster the content loads, the less chance the user will leave the resource. Moreover, search engines estimate the general site's speed themselves.

Besides increasing the files loading speed, the content delivery network also has other advantages:
Server traffic decrease. In case of a default hosting, reception, processing and forwarding all the data to every user is provided by only one server. CDN helps to distribute this load among several servers soundly.
DDoS protection. Distributing also provides additional data protection. CDN is a relatively complicated information transmission system. Therefore, hacking it takes rather more time and resources.
Variety of use. CND can be used for speeding up loading of audio and video files, complicated animation and even games. Any sort of sites can be expedited: online store, information resource and sites promoting certain services.
Helps the site to work faster. Using CDN helps to select the optimal location and number of the chain components. Files will be loaded equally fast for all the users regardless of the locations.
Use of the CDN helps to cut wastes on the hosting optimization. Of course, you will have to spend some money to integrate, adjust the CDN and its service. However, it is still worth for money and constant development of the hosting is rather more expensive and problematic.

How to choose the CDN provider

There is a great deal of CDN providers. Each of them offers its price for the CDN, term of use and quality of the service. Moreover, choosing the right provider depends on plenty of individual factors and site features. Here are the most common of them:
A number and location of servers. On the site of the CDN provider must be a world map showing all the company's servers.

The best is that provider, servers of which are located most closely to the target audience. And the more servers, the better. Provided that, you can choose the amount and location of the optimal server.
Servers traffic. Even though the CDN servers allow rational distribution of the traffic, a number of terabytes available for use are limited. You shouldn't connect to overloaded servers as they may work slowly and break down at all.
Caching terms. For providing the maximum files loading speed, servers copy and save site's and users' data. There are two basic caching methods:

  • caching of the whole content. This is the most expensive option, as the fast loading is provided even at the first visit. As we never know what exactly pages will be visited, the site is cached entirely beforehand.

  • the first visit caching. This is the most widespread option. User's device saves visited pages only. Usually, the first entering a certain page is the slowest. While all the further visits, the files will be loaded times faster.
Terms of service. Before signing a contract with the provider, it is better to pay attention to some issues which may occur while using the service.

Find out how the traffic will be provided if one of the servers crashes. Will be the price changed for a period of the server recovery? Are there any compensations or discounts for the audience loss which happened because of the provider? Also, it worth discussing sanctions applied for both sides in case of non-compliance.
Additional CDN services. Besides the servers, quite often providers offer their clients various additional services. These can be: keeping statistics and analysis, ability to change the caching terms, etc.
Payment terms. How is the service paid for? How often? Do clients have to pay for the traffic used or the period of using the network? What if an amount of the traffic used is less than set out minimum?
It's important to choose the proper CDN, consider servers' location as close to users as it is possible. We advise the needed servers to be chosen based on the analysis of your site metrics. This will show which region includes the vast majority of users. Also, site specificities and your target audience should be considered.

All these nuances have to be taken into account before paying. Moreover, it would be great to know whether the company signs contracts with clients and what are the terms of termination in case if you, for instance, decided to change the provider.

The most popular providers

According to Hostings.info rating, the most popular CND providers are InterServer.net in the USA and 1&1 IOINOS.com in Europe. Both of them have servers located all over the world.

How to set up CDN?

There are tens of various ratings and providers overviews on the Internet. Site owner just has to determine which exactly files are to be optimized and direct them to the system.

Let's have a look at several popular CDN providers.


This is a relatively young company which works only six years. However, for this time, it managed to base its servers worldwide and powered more than 45 thousand websites. CDN77 has more than 35 data centers located all over the world.

Price for the CDN depends on terabytes needed. There are four monthly plans starting from 6 TB and ending with 100 TB per month. Also, there is another pricing type which considers payments for the amount of the used traffic and severs chosen.
CDN provider CDN77


One of the world's largest CDN hosting. The company was established in the USA more than 14 years ago. They count nearly 155 servers systems worldwide. Most of them are located in Europe, the US and Asia.

There are four pricing plans on the site. Furthermore, one of them is free. It is suitable for little websites, blogs, etc. The minimum domain service price is 20 USD per month. In addition, the company offers plenty of other useful tools for site optimization and protection.
CDN provider CloudFlare


The company works since 2012. There are eight tariff plans on the site, offering clients absolutely different terms of use. The minimum price is 0.04 USD per GB. All the plans consider DDoS protection, CDN storage, CDN SSL and many other features.
CDN services CDNsun

How to set up CDN?

Let's consider how to set up CDN to the site from the example of CloudFlare. All the platforms have approximately the same registration and adjustment procedures. So, the following instructions can be considered to be universal.
Get registered on CloudFlare. Enter your Email, create a password and click Create Account.
Registration in CloudFlare
Site registration. Enter the site domain as it is shown in the example (without www and http) and click Add Site > Next.
Adding site to CloudFlare
Choose the free plan and click the confirm button.
CloudFlare prices
Create a CNAME for the registered URL, click Add Record and Continue.
CNAME creation in CloudFlare
CloudFlare will update your domain within 24 hours. In order to connect the site to the CDN, you need to replace the current domain with a new one.

How to speed up certain files loading?

You can speed up the whole site, but it will be more expensive than to do the same but with a part of it. It is much better to identify the most "heavy" files which slow down page loading. Also, it's worth to optimize only those elements which are almost never changed, such as images, javascript, CSS.

Content delivery networks work automatically, so entering the address of an existing server in settings is pretty enough to connect the site.

To connect the CDN to some particular page elements, you have to encode new static elements' addresses (images, javascript, etc.). To do this, you need to replace the current files path with the one connected to the CDN.

For example, here is a certain file code:
<link rel="stylesheet" href="/css/style.css"/>
Add this very address to the code in the CDN server and the result is:
<link rel="stylesheet" href="http://user123.clients-cdnnow.ru/css/style.css"/>
A site protocol plays an important role. If the site is available only with HTTPS protocol, then it also has to be encoded:
If there is a standard protocol on the site, the code also may not include it:
Do the same with every particularly taken file. After that, it is better to check how the site works. Refresh the pages, follow some links, view animated elements if there are such. The site has to work as earlier. The page loading speed won't change considerably and, most likely, you even won't see the difference as the CDN system is aimed at optimizing distanced from the main server processes.

If you see that after the refreshing, site works incorrectly, e.g. images don't appear or something like that, most probably you have mistaken while encoding. This may be an odd dot, gap or vice versa their absence. Check the code and correct the mistake.


If you need to speed up site loading for users from the far regions, content delivery network (CDN) is a great solution.

Don't expect that after the CDN is integrated, the site loading will become 2-3 times faster. Everything depends on the size of the loading files, quality of the CDN's work in general, etc.

Increasing loading speed for 1-2 second is a great result. Sometimes, it happens that a 0.5-second difference positively influences customers behavior and their attitude to the content.

This article is a part of Serpstat's Checklist tool
Checklist at Serpstat" title = "What is a CDN and how to set it up 16261788304404" />
Checklist is a ready-to-do list that helps to keep reporting of the work progress on a specific project. The tool contains templates with an extensive list of project development parameters where you can also add your own items and plans.
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