How to Tell What a Website is Built With – 2 Easy Ways

computer showing website code

There are a lot of reasons you might want to know how a website was built. Are you a web designer looking at a potential new client’s website? Are you scoping out your competition? Sometimes you just want to know what platform a website is built with. There are several ways to find out.

In general, there are two ways to determine what a website is built with. You can look at the source code or use a tool like Builtwith.com or Wappalizer.com. It’s a good idea to use both the source code and a tool to find out the most information about how a website was built.

With so many different content management systems and website builders out there, figuring out how a website is built can be helpful. You can use tools to identify not only the platform but also which themes and plugins were used. You can also identify where the website is hosted and other information about the website.

Tools that tell you what a website is built with


Builtwith.com, a tool to tell you how a website was built

Builtwith.com is easy to use. All you need to do is type in the name of the website and press lookup. It will generate a list of the analytics and tracking platforms used on the website. It will tell you what content management system is used. If the site is built with WordPress, WIX, Weebly, or Squarespace, it will list all the widgets or plugins installed on the site. It will also tell you if the site is mobile-friendly on Android and iPhone, whether or not the site has schema markup, the javascript libraries it uses, where it is hosted, information about the SSL certificate, and which advertising platforms it uses.


W3techs, website tool that provides technology information about a website

W3techs.com provides much of the same information as Builtwith. To use it, go to https://w3techs.com/sites. Enter the URL of the website and click on site info. If the site has already been crawled you will see a list of info about the technology used on the site. If it hasn’t been crawled, you will see a message that says, “W3Techs has not yet crawled this site! Do you want us to crawl it now?” Click crawl now and a report will be generated.

The report will tell you the website’s title and description, which content management system it uses, the server and client-side programming languages, their website hosting provider, domain name provider, information on their SSL certificate, which analytics and advertising platforms they use, and the types of structured data the site uses.


SImilartech.com provides you with the technology used on any website

Similar tech provides you with information on the technology used on any website. You can use it for free. Go to Similartech.com. Type the name of the website in their search bar and it will display the results. This will tell you the advertisers the website works with, who they use for marketing and analytics, what CMS they use, the page builder they use, which plugins they use, their website hosting company, domain name provider, and the type of structured data they use on the site.

Browser Extensions that will tell you what a website is built with


Wappalyzer is a browser extension that tells you more about how a website is built

Wappalyzer is another tool that will identify what a website is built with. It is a browser extension that works on Chrome, Firefox, and Edge. To use it, add the extension to your browser. Then just visit any website you want to check out. Click on the extension. A window will pop up with a list of all the technologies used on the website.

This will tell you what content management system is used, what analytics and platforms are used, which javascript libraries are used. If the site is built in WordPress it will tell you what page builder is used.


WhatRuns is a browser extension that tells you what platform a website uses and other technology information.

WhatRuns is a Chrome extension that will tell you what CMS a website is built with and other information about the site. After you install the extension, you can visit any website to use it. When you visit the site, just click on the extension. A window will pop and display information about the site including what CMS it uses and what version, the website’s themes and plugins, the type of web server it’s on, what programming language it uses, and the analytics platform it uses. The technology information is not as extensive as some of the tools listed above, but if you are just trying to find out what CMS the website is built with, it’s a pretty good tool.

How to Check the Source Code for Website Identifiers

If you are experienced with coding, you can check the source code of a website to determine how it was built. Even if you don’t know how to code, you can still view the source code to find identifiers.

Before content management systems like WordPress, WIX, and Squarespace, most websites were built with a programming language like HTML, PHP or ASP. You may still find websites that are hand-coded, in which case you won’t find identifiers in the code. You also won’t find a CMS listed if you check it with one of the tools listed above. This is one of the reasons it is useful to check the source code and not just use a tool.

To check the source code, visit the page and right-click on it. Then click view source. This will show you the source code for the page. This will provide you a lot of information about the site. You should be able to determine how it’s built by looking at the code. WordPress, WIX, Squarespace, and Weebly all have identifiers you can find in the code.

You can visually skim the code for identifiers or use the find on page feature to look for identifiers. Here is a list of identifiers for the most popular content management systems.


A WordPress website will contain the identifier “wp-content” in the code

Theme Identifiers 

You can find the name of the theme used by looking at the code underneath the <style> tag.. Look for <link rel=’stylesheet’. Next to it you should see an identifier for the theme; for example, astra-theme-css-css.

Page Builder Identifiers

You may be able to identify which page builder was used as well. Many of the page builders leave identifiers like “wpb” for WPBakery page builder or “elementor” for Elementor page builder in the code.


WIX leaves an identifier at the top of the source code. Look for <meta name=”generator” content=”Wix.com Website Builder”/>. You will also find “wix” throughout the code.


At the top of the souce code you will see a Squarespace identifier that looks like this <!– This is Squarespace. –> You will also see “Squarespace” throughout the code.


Weebly uses the identifier wsite throughout its source code. You can also do a search for weebly and find it in the source code.

Why Identify the Platform a Website is Built With?

If you are a web designer planning to work with a new client, knowing which platform they currently use can help you plan your strategy. Sometimes when you work with clients, they don’t know how their website was built, especially if they worked with another designer or are not tech-savvy. 

If you are moving a website that was not built with WordPress, there are challenges. You can’t just import a website from Weebly, WIX, or Squarespace over to WordPress. Additionally, there could be site performance issues, SEO issues, or other problems for you to deal with if you aren’t familiar with the other platform. If you know ahead of time what platform was used, you can plan out the best way to take over the website or move it over to a CMS you are more comfortable with.

Knowing what platform a website is built with also provides you with a wealth of useful information. If you are scoping out a competitor and check their source code, you can see what theme or plugins they used to build their website. For example, if your competitor has a cool slideshow or carousel on their website, you can discover what plugins they used to create it.

Looking at other websites is a great way to get inspiration and ideas for your own design. If you see a website you like, take a look at their source code. This is a great way to improve your web design skills, Look at other websites and find out how they were designed. Then you can use the same plugins, themes, or fonts in your design.

It’s best to use both a tool and look at the source code. A tool will tell you most of the information you want to know about how a website is built, but by examining the source code you can discover other details like image dimensions, meta tags and descriptions, and details about their website’s search engine optimization.