One of the most common questions we get at Drupal beginner classes is, "How can I tell if a site is built in Drupal?"
We get that question because it's just not possible to know the answer without a few tips and tricks.
If you look at a website such as WhiteHouse.gov, there is no way of telling if it's built Drupal. The design of a site is completely independent from the platform it uses.
We're going to give you 5 ways to tell if a site is built in Drupal. Not all of these suggestions will work on all Drupal sites, but taken together they should give you a clear answer.
Option #1. Check the Source Code
One of the most reliable ways to show if a site is using Drupal is to check the source code.
In the source code, check to see if important files are being loaded from the /sites/ folder. This identifies all Drupal sites, except for Drupal 8. This example is taken from WhiteHouse.gov:
If you find a Drupal 8 site, you will see files loading from the /core/ folder. This screenshot is taken from Dries' site at http://buytaert.net:
You can also search the source code for the words "Drupal", which will identify any version of Drupal:
You can also search the source code for the names of key modules such as "Views", "Panels" or "CCK":
Option #2. Try to access certain files
Some sites may remove this file or block access to it, but if you CHANGELOG.txt to a site's URL, you can often find useful information about the site. For example, view https://drupal.org/CHANGELOG.txt and you can tell that Drupal.org is still running Drupal 7.
Other files that you can do this with include:
Option #3. Visit the User URLs
One common identifier of Drupal sites are the URLs for user pages.
The URLs /user/ and /user/password and /user/register/ are commonly used to allow people to login, recover their password or register.
For example, here's https://petitions.whitehouse.gov/user
Option #4. Check websites
There are websites that can try and identify the technology behind websites. http://builtwith.com is one of the most popular sites that does this:
It correctly identifies WhiteHouse.gov as using Drupal:
There's also the very logically named http://isthissitebuiltwithdrupal.com:
That site gives very logical and clear answer
Option #5. Check the Expires header
An expires header is the most geeky way to check for Drupal sites. Web servers use an expires header to tell the client how long a component can be cached. Use a site such as http://web-sniffer.net to check your site:
And in the results, look for the Expires date. You're looking for Sun, 19 Nov 1978 05:00:00 GMT. What is special about 19 Nov 1978? It's the birthday of Dries Buytaert, the founder of Drupal.