Tag Assistant uses two methods to verify the implementation of a Google pixel: source code scan and header request checks. The former is used to detect specific issues with the implementation of the code, whereas the latter is used to verify that the script fires at all.
For source code scanning, Tag Assistant uses a pre-defined list of implementation checks to perform for each tag. When the web page loads, Tag Assistant scans the source code of the web page and looks for a specific Google pixel. Once Tag Assistant has identified a Google pixel, it compares the pixel implementation on the page against the the correct/standard implementation as well as the pre-defined list of implementation checks. When the correct implementation is found, Tag Assistant returns a green status. When one of the incorrect implementations is matched, a red status is returned along with recommendations and support documentation.
Header checks are used to determine whether or not the specific pixel actually fired. When one of the pixels on the page fires, it sends a request to Google servers containing relevant information, such as account number, profile number, or labels. This extension will monitor all of the requests from the web server to ensure that the proper request is sent to our servers.