Google Tag Assistant is Google’s free tool for seeing, in real time, which tags fire on your site and what information reaches Google Analytics and Google Ads. You go to tagassistant.google.com, enter your site’s address, browse like a customer, and Tag Assistant lists every tag that fired, on every page and every click. It’s how you find out whether a conversion works before spending budget on it.
A tag that doesn’t fire is the most expensive and most silent problem in digital marketing. The campaign runs, the report shows zero conversions, and the conclusion becomes “Google Ads doesn’t work.” Most of the time, the sale happened and the tag just didn’t report it. We explain what this does to your account in Google Ads isn’t converting.
Today’s Tag Assistant and the Legacy version
There used to be a Chrome extension called Tag Assistant, now known as Tag Assistant Legacy. It was replaced by the web version, at tagassistant.google.com, which works together with Google Tag Manager’s preview mode. If you come across tutorials using the old extension, those steps no longer apply.
There’s also the Tag Assistant Companion extension, which just helps the web version open the site in the same window. It’s optional.
How to test your site with Tag Assistant
- Open Tag Assistant. Go to tagassistant.google.com and sign in with the same Google account that manages your GA4 or Tag Manager.
- Add your domain. Click Add domain and enter your site’s address.
- Browse like a customer. A new window opens your site in debug mode. Visit pages, click on WhatsApp, fill out the test form.
- Read what fired. Go back to the Tag Assistant tab. On the left, you’ll see a timeline of events (page loaded, click, form submission). Click on each one to see which tags fired and which didn’t.
If you use Google Tag Manager, you get to the same place by clicking Preview in the container. The difference is that through Tag Manager, you also see changes you haven’t published yet. See how Tag Manager works.
What to check in each test
- The Google tag shows up only once. If the same ID appears twice, Analytics is installed twice.
- The ID is correct. The G- for Analytics and the AW- for Google Ads need to match your account. It’s common for a site to still have the ID from an old account.
- The conversion fires at the right moment. It should trigger when the form is submitted or the thank-you page opens, not when the form page loads.
- The events have the right parameters. For a purchase event, check that the value and currency are filled in.
- Nothing fires before consent, if the site has a cookie banner with blocking.
Checking on the GA4 side
Tag Assistant shows what the site sent. To see what GA4 received, open the DebugView report in GA4, under Admin. While Tag Assistant is connected, your browsing shows up there, event by event, with the parameters. If the event appears in Tag Assistant but not in DebugView, the problem is the ID or a GA4 filter. GA4 setup is covered in GA4: how to set it up from scratch.
Checking on the Google Ads side
In Google Ads, under Goals, Conversions, each action shows a status. An action with no conversion recorded in many days, or with an inactive tag, is a sign that the Tag Assistant test needs to be redone. The step-by-step for setting up the conversion is in Google Ads conversion through Tag Manager.
Common mistakes
- Testing with an ad blocker turned on. It stops the tags from firing, so the test looks like it failed.
- Testing only the homepage. The conversion happens at the end of the path. Walk through the whole path a customer takes.
- Testing with a real form without telling your sales team. Use a name that makes it clear it’s a test.
- Assuming that “it fired” means “it arrived correctly”. A tag can fire with an empty value or the wrong ID. Open the tag and read the data.
Frequently asked questions
Is Tag Assistant paid? No, it’s free.
Do I need to install anything? No. It runs in your browser. The Companion extension is optional.
Does Tag Assistant work with the Meta pixel? It shows Google tags. For Meta, use the test events tool in Events Manager, or check the pixel firing inside Tag Manager’s preview mode.
Want us to test your tags? The free Google Ads audit includes a review of your account’s conversions. And our conversions and CRM service sets up and tests everything for you.