Preview & Debug

GTM's Preview mode (Tag Assistant) is how you verify your work before publishing. In your GTM account click Preview, paste the URL you want to test, and Tag Assistant opens it in a new tab connected to a debug session.

What Tag Assistant shows you

• Tags, which fired and which did not, on each event.
• Variables, the resolved value of every variable at that moment.
• Data Layer, every push in order, so you can confirm your events.
• Consent, the current consent state for each event.

That is exactly how these lessons work: each one loads your container and pushes real events, so you point Preview at the lesson URL and watch your tags light up, the same loop you'll use at work.