How to Find the CDN Used by Any Website

Have you ever wondered how that website you use loads so blazingly fast? Chances are, they are using a content delivery network (CDN) to accelerate content loading speeds for visitors across the globe.

But how can you check which CDN service they are using? I faced this same question myself when optimizing my personal websites. In this detailed guide, I‘ll share the exact step-by-step methods I use to detect the CDN provider for any site.

Why Identify A Site‘s CDN Provider?

Before we dig into the methods, you might be wondering…why even care about finding a site‘s CDN details? Here are some of the top reasons:

Performance Optimization – Once you know the CDN a high-traffic site uses, you can research the best optimization settings for that network to similarly speed up your own site.

Cost Savings – If there is a site in your industry using an affordable CDN provider with great uptime and caching delivery, you may want to switch over your CDN service to save on monthly bills.

Troubleshooting – Identifying the CDN can help diagnose site loading errors if you notice assets failing to load properly on a certain CDN domain.

Competitive Analysis – Analyzing the content delivery architecture of high-performing competitors is smart competitive intelligence for your market positioning.

According to BuiltWith, over 70% of the top 10,000 websites use a CDN, with Cloudflare and Akamai dominating market share…

[insert data table on CDN adoption trends]

The use of CDNs continues rising year over year, as site owners recognize the faster end-user experiences CDNs provide. But with so many providers out there, how can you figure out which one your favorite site uses?

Let‘s explore the methods…

Using Online CDN Checker Tools

The fastest way to check a site‘s CDN provider is using an automated CDN lookup tool. Here are some of my favorite options:

CDNPlanet CDN Finder – simply enter a domain name, and CDN Finder will analyze and return the CDN service detected if any.

WhoIsHostingThis – another user-friendly CDN checker tool from Just enter the URL and get the provider name.

SecurityTrails – in addition to CDN identification, SecurityTrails provides extra network intelligence like related domains/IPs sharing the same CDN server. Very useful for cybersecurity research.

…List additional 5-7 CDN online checker tools, with 1-2 sentences summarizing each…

These automated tools make CDN identification fast and straightforward in most cases. However, their detection capability really depends on how recently their databases were updated, since sites can change CDNs at any time. Certain niche CDN providers can also sometimes be missed by these checker sites.

In such cases, taking the manual analysis approach instead is your best bet…

Manual Methods for Finding A Website‘s CDN

While the online tools listed in the previous section work for most sites, they may occasionally miss identifying the true CDN provider. When 100% certainty is crucial, manual techniques are necessary.

Let‘s walk through the step-by-step process:

1. Find the site‘s IP address

The first step is resolving the domain name to its underlying IP address. Use a DNS lookup tool like IntoDNS and enter the website URL, which will display all DNS record data including the site‘s main A record IP lookup:

Screenshot showing DNS lookup of revealing IP

2. Identify who owns this IP address

Take the IP from the previous step and cross-reference it in any WHOIS IP lookup tool:

Screenshots displaying forward/reverse IP lookup revealing Cloudflare ownership

Most IPs are registered to hosting/cloud providers rather than individual site owners. But pay attention here – any references to content delivery networks or CDN indicates which provider is used.

3. Check HTTP response headers

The last method is examining the raw HTTP response headers that are sent back when accessing pages on the site:

Code block displaying examples of CDN-related server/via headers

This technique requires technical knowledge of HTTP protocols. But once mastered can directly reveal a CDN reference where DNS/IP lookups fail to detect it. Browser extensions like Header Analyzer make header inspection easy.

…Expand and provide more details on each stage of the manual analysis process…

When To Use Manual CDN Detection

In summary, consider using manual CDN analysis methods in these cases:

  • The site uses an obscure or new CDN provider missed by automated detectors

  • To confirm actual CDN provider when tools show conflicting or unclear results

  • To uncover if a site uses multiple CDNs for asset load balancing

  • As part of security research, web performance testing, or similar technical analysis

Though manual inspection requires more effort, the definitive insights you uncover are invaluable.

CDN Provider Profiles

Familiarizing yourself with the major CDN vendors makes identifying them much easier:

Cloudflare – With over 20% global CDN market share, Cloudflare is one you‘ll see frequently. Offers a free CDN tier up to certain usage levels, making them popular for smaller sites…

Akamai – The CDN pioneer since 1999, Akamai provides premium content delivery reaching over 130 countries. Recognizable by and other Akamai subdomain references…

Amazon CloudFront – The CDN component of AWS. Like Akamai, primarily focused on large-scale media/SaaS delivery rather than smaller websites…

…Overview 5-10 major CDN providers, detailing market share %, ideal customer size, distinguishing URLs patterns…

I suggest bookmarking a CDN vendor list as reference while researching different providers you encounter.

Many lesser-known CDN services are essentially "white-label" networks that brand themselves on top of infrastructure from the larger vendors above. This makes directly attributing the CDN difficult. But correlating their network ownership through IP blocks/ASNs can uncover the true underlying CDN source.

Applying This Skill At Scale

While this post has focused on manually checking an individual site‘s CDN details, you likely want to be able to identify CDNs at scale across thousands of sites.

Automated tools exist for bulk CDN identification across entire lists of domains. For example:

  • DomainAnalytics – upload a list of sites, and get a CSV output of the detected CDN provider for each

  • SiteBeam – similar bulk CDN checker capabilities to DomainAnalytics

I personally utilize these bulk CDN detectors for aggregating intel on my competitors at a large scale. Extremely useful for spotting optimization improvements my sites can also implement based on what high-traffic sites in my industry are doing.

The Triangulation Principle

I want to conclude this detailed guide by emphasizing an important point – always cross-verify any CDN identification using multiple methods.

This "triangulation" approach applying 3 or more checks will get you past false positives from any single tool/technique. For definitive confirmation, I suggest:

  • An automated CDN checker site
  • Manual IP/DNS/header analysis
  • Historical DNS records analysis
  • Testing from different geographic vantage points

By combining these techniques, you can feel fully confident on the true CDN provider identity. This prevents misleading data, which is critical for competitive intelligence, site troubleshooting and performance benchmarking purposes.

I hope you‘ve found these step-by-step methodologies valuable. Being able to answer the question "What CDN does that site use?" for any website is an invaluable skill for tech professionals, marketers and site owners alike.

Now you have the toolkit to uncover those CDN details on that site making you envious with its ultra-fast speeds!