WordPress Theme Detectors are utilities that can detect what WordPress theme a website created using WordPress was built with. There are various types of these utilities. The most common are websites that can take a URL and report back the theme used or browser extensions that can be turned on when browsing a site to detect the theme.

How do WordPress Theme Detectors work?

WordPress Theme detectors look at the source files loaded when loading a website to scrape the theme’s name out of these files. This works effectively because all WordPress sites have a specific set of files and file structure, so the detector knows the files to look for in a WordPress website. 

Looking at the files downloaded to display a WordPress website, you can see the theme name in a style.css style sheet file. There may be different text or even a different filename, but there should be a file that will have a comment at the beginning of it that specifies the theme name and other information.

Once this information has been retrieved, the detector will usually have a database to look up any information it has stored about the theme, for example, where you can buy it and the price. The result of the information from the style sheet and the detector database is then presented to the user.

Examples of Theme Information

To see the best examples of theme information for a given theme, you can look at the themes built by WordPress. Not all fields in the header comment are required. The WordPress-built themes will populate the required attributes and some more with decent enough detail that will help you when building your themes.

The following example shows the theme information from sonymusic.com. This is a popular website and shows that WordPress sites are capable of handling large traffic sites.

/*
Theme Name: Sony Music
Author: RGNRTR Custom Team
Author URI: http://www.rgenerator.com/
Description: Sony Music Entertainment Official Site.
Version: 1

This theme, like WordPress, is licensed under the GPL.
Use it to make something cool, have fun, and share what you've learned with others.
*/

As you can see here, the theme information is a bit limited as the designers of this theme are only giving the basic required details. It tells us the name, author, the author’s website, description and version number.

As a side note, the version number is used in the WordPress admin panel to determine if a new version of your theme is available. If the version number is incremented, you will be prompted to update your theme to the latest version.

The following style.css header comment is from the WordPress Twenty Twenty-One theme.

@charset "UTF-8";

/*
Theme Name: Twenty Twenty-One
Theme URI: https://wordpress.org/themes/twentytwentyone/
Author: the WordPress team
Author URI: https://wordpress.org/
Description: Twenty Twenty-One is a blank canvas for your ideas and it makes the block editor your best brush. With new block patterns, which allow you to create a beautiful layout in a matter of seconds, this theme’s soft colors and eye-catching — yet timeless — design will let your work shine. Take it for a spin! See how Twenty Twenty-One elevates your portfolio, business website, or personal blog.
Requires at least: 5.3
Tested up to: 5.7
Requires PHP: 5.6
Version: 1.3
License: GNU General Public License v2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html
Text Domain: twentytwentyone
Tags: one-column, accessibility-ready, custom-colors, custom-menu, custom-logo, editor-style, featured-images, footer-widgets, block-patterns, rtl-language-support, sticky-post, threaded-comments, translation-ready

Twenty Twenty-One WordPress Theme, (C) 2020 WordPress.org
Twenty Twenty-One is distributed under the terms of the GNU GPL.
*/

Here you can see several extra properties added to the theme information. You should consider adding these properties to your theme if you build your own.

Example Theme Detectors

The first theme detector I will discuss is https://www.wpthemedetector.com/ This website does one thing, and that is detecting what WordPress theme a site is using. Testing out this detector, we get the following information:

As you can see, the detector could determine the theme name but not the version, author or whether this theme is available to download or buy. This makes sense, as the theme seems to be custom-built for Sony. Interestingly, the Version wasn’t able to be determined by the detector even though it was clearly labelled as version 1 in the style.css file.

The second theme detector I tested was scanwp.net. Using the sonymusic.com website as the test subject, these are the results:

As you can see, this detector has picked up on the Version tag, and it has also picked up the author and description fields that were not present from wpthemedetector.com.

The third detector I tested was isitwp.com. Using sonymusic.com as the test subject, here are the results:

As you can see, there is very little information displayed using this detector. The detector could find the theme name but returned no other theme information.

The fourth theme detector I tested was gochyu.com. With sonymusic.com as the test subject, here are the results:

So this test detector returned no useful information.

The fifth detector I used was wpdetector.com. Here are the results for sonymusic.com:

This detector provided everything except the author’s URI, so not a bad result.

The sixth detector I used was https://whatwpthemeisthat.com. Here are the results for sonymusic.com:

This detector could gather all of the fields from the style.css header, and it also returned a screenshot of the site, which was a nice touch.

With these six detectors, I then tested a non-custom theme site at wertmacher-werbeagentur.com. By non-custom, I am describing an off-the-shelf use of a theme.

The following is an image of the header from the style.css file:

This is the result from whatwpthemeisthat.com:

From the list of provided fields, the only fields that were missing were the License URI, Tested Up To, Text Domain and Tags fields. These aren’t technically that useful when determining the theme a website is using, so I don’t take this as being negative.

Back on wpdetector.com, this site produced some interesting results:

As you can see, the detector has found that the site uses a child theme which whatwpthemeisthat.com did not detect. The other positive fact about the child theme information is that the detector could retrieve each theme’s version number.

Apart from the child theme detection, several fields were missing, including the author and theme URIs. These tags would have been useful as they give the user a link to investigate the theme further.

Next, I tested the site through isitwp.com:

The results are fairly lacking here. Firstly, the only information retrieved was the theme name, no versions, authors etc.

Secondly, the theme wasn’t found in their database even though it can be found on the WordPress site here: https://wordpress.org/themes/telegram/, so based on this, there isn’t any reason why the detector shouldn’t have returned more information.

The next test was through scanwp.net. Here are the results from that test:

The results were reasonable. The theme name, author, URI and description were all returned. Even the price of the theme and the store where you can get the theme from was included in the results. Notably, the fact that the site uses a child theme that wasn’t identified is the only real negative here. Keeping in mind, however, that a child theme is still based on the main theme, you could give any detector a pass in not identifying this.

Next, the test was run through gochyu.com. Here are the results:

This site did very well and displayed a nice set of visual boxes for the tags element in the header file. All relevant information was returned with this search.

Finally, I tested the site through wpthemedetector.com. Here are the results:

As you can see from the above screenshots, this detector returned all information, including the fact that the site uses a child theme. 

Here is a quick summary of the results (from my limited tests). The first table shows the results of sonymusic.com, a custom theme built for the Sony Music website.

sonymusic.com

From this table, we can see that the top detectors were scanwp.net and whatwpthemeisthat.com. 

The next table summarises the results from wertmacher-werbeagentur.com

Wertmacher-werbeagentur.com

The next site I will try with wpthemedetector.com is 007.com. Let’s look at the style.css header information first and then compare that with the results of the theme detector.

Conclusion

Of the top 6 Google results when searching for WordPress theme detectors, most of these detectors were accurate. The best of the six would have to be whatwpthemeisthat.com, with a special mention going to scanwp.net.

Of the above sites, only a couple could detect whether a theme was a child theme. Provided the detector could return the theme name and some information about the theme, the presence of a child theme is probably not that important to the end user who wants to know what theme was used to build the website.

These tests were only fairly plain WordPress deployments and do not reflect results found for all different varieties of WordPress deployments. For example, the site 007.com uses a build-engine to build the site, and because of this, it is a bit trickier to determine the theme and details (although it can be done).

Don’t forget to check out my other WordPress articles here which contain links to common concepts and examples in React.

Also, you can follow me on Twitter/X here! And now, mastodon: @bernieslearnings@mastodon.social