To see the ID5 usersync pixel fire, open Developer Tools in your browser and go to the Network tab. Filter for id5-sync.com and you will see the http requests it makes.

Note: This example shows a simple img pixel and does not pull in GDPR consent signals from the CMP. This is for illustration purposes only, in a production site you should always check for a CMP and consent signals. Take a look at our JS example for a more robust way to deploy our usersync pixel.