How to Check if Google Tag Manager is Working?

Оnce you finally set up Google Tag Manager for your website, you need to make sure your efforts pay off. Otherwise, you'll just sit there waiting for some data to appear in GA4 reports and find nothing after a while. 

That's exactly why you need to check if Google Tag Manager is working right after you install it on your website and debug GA4. Though it might be overwhelming to set up GTM, let alone test it, we'll try to make it simple.

Today you'll find 5 simple ways to test Google Tag Manager that work for both — developers and non-technical people. However, note that they are not alternatives to each other. We recommend using several methods for testing.

Should we start?

1. Enable Preview And Debug Mode

The easiest way to check if Google Tag Manager is working properly is to use the resource you already have — Google Tag Manager itself. There are preview and debug modes that enable you to preview created tags and fire them on your website. 

To enable preview mode, navigate to your GTM homepage and choose the container you want to test. Find the Preview button at the top left in the navigation bar. 

Preview Google Tag Manager

Once you click on the Preview button you need to specify your website URL.

Connect tag assistant to your website

The URL will open in a new tab. If everything is set up properly you should see the following message back in the Google Tag Manager.

Connect Tag Assistant with your store

Click Continue to see the status, events and tags fired.

GTM tags

It's a step where you can go to your website, perform a specific action and see the tags fired.

Fire events in GTM

Additionally, on the page that has opened in a new tab, you'll see a notification about the tag being connected.

Google Tag Manager debug mode

Important: every time you make any changes to the tags and preview them in GTM, you need to publish them by clicking Submit

Submit changes to Google Tag Manager

2. Use Google Tag Assistant

If you're looking for the most hassle-free way to test Google Tag Manager tags, the Tag Assistant Legacy Chrome extension is the best option. 

Note: once you add this extension to Chrome, you need to enable it before using it on a certain page. 

To check if GTM is working with Tag Assistant, go to the homepage or any other page and click on the extension icon on the right top side in the browser address bar. Choose Enable and reload the page.

Enable Google Tag Assistant

Then click on the extension icon again to see all detected tags. 

Tag assistant analytics

3. Check Source Code

The other way how you can check if Google Tag Manager is working is by checking the GTM container in the source code of your website. 

Overwhelming already?

Go to the homepage of your website, right-click anywhere on the page and choose View page source from the web browser tools. Alternatively, you can press the Ctrl+U combination to view the source code.

Website source code

Once you see the source code of your homepage, press the Ctrl+F combination to start searching for the GTM container code. 

Type gtm.js in the search bar and find the GTM container code between the <!-- Google Tag Manager --> and <!-- End Google Tag Manager --> tags.

Find GTM code in source code

4. Use Developers Console

This one is probably one of the hardest ways to test GTM tags if you're not comfortable working with developers' tools. Still, it's simpler than it seems.

First, you need to navigate to your website homepage, right-click on the page and select Inspect from the browser tools. 

It opens the developers' console at the bottom of the page. Initially, you'll land on the Elements tab. But you need to switch to Network.

Note: make sure to select the Disabled Caches and Preserve log checkboxes, and switch to All.

Developer Tools Network

Then paste gtm.js in the search bar and refresh the page.

gtmjs code

As a result, you should get something like gtm.js?id=GTM-5QHL4MW which is your GTM container ID.

GTM container code on a page

5. Check GA4 Realtime Report

Since you, most likely, need GTM tags to track important events on your website, checking GA4 real-time reports is also one of the options. Go to Google Analytics > Reports > Realtime and check the real-time users and their activities. This indicates that the Google Tag Manager works properly. 

Google analytics report

You will see the traffic sources, users and events they currently trigger on your website. Once you have enough data about your audience, their preferences and tendencies, you can use that information for your marketing campaigns.  

In case you manage an eCommerce store on Magento, you just have to check the Magento 2 Google Tag Manager Extension to track add_to_cart, add_to_wishlist, purchase, create an account and many other events. It will help you to boost conversions and streamline your strategy.