Google Tag Manager as a Tag Management System

by Ricardo Cristofolini

With everything happening currently in the world – COVID19, isolation, etc., it’s not uncommon that a lot of website owners are noticing an increase in traffic. People already spent a lot of time online, but now, more and more users are replacing store visits with button clicks.

For businesses, this is great news and if properly collected, all of the data from these users can be the decisive point when choosing between launching a new promotion or discount or waiting for a better market opportunity.

But then comes the question: How is that data going to be collected? We’ve all heard about web analytics tools that track and report website traffic such as Google Analytics and Adobe Analytics, and even behavioural trackers such as Hotjar or Clicktale, but in websites where a more in-depth understanding is desired, or decisions, or future investments are based on custom reports and analysis, a Tag Management System is necessary. Having a Tag Management System ensures that, in case of an extensive analytics stack, each individual tag/tool will be capturing consistent values across a multitude of tooling.

What is a TMS?

Before we dive in and start collecting data, let’s understand what a Tag Management System (TMS) is. TMS is a software that can be used to manage tracking and marketing tags, custom javascripts snippets – variables that hold information, etc. used in digital marketing. Currently, TMS is the most effective way to implement third-party code on your website, as it unifies what otherwise would need to be implemented, tag by tag, JS by JS, onsite, incurring a significant amount of development cycles to realize.

Now, you may be asking the questions, “should everyone use a TMS? Why is it so important?

Short answer, yes. Even if you have a small website with only one analytics tracking that can be deployed directly into the site code, it’s highly recommended to do so through a TMS. Once you understand how powerful a tag management system can be, you will definitely want to use it.

We all look forward to having better and bigger sites with lots of visitors, but, in order to drive better results and provide your visitors with what they are looking for, more implementation is necessary. This is where a can really help you out.

For example, each tracking software you decide to have in your site (HotJar, Google Analytics, Clicktale, etc.) is composed of a script that needs to be loaded on the page. Just with this example, we have 3 scripts that need to be loaded.

Now, keep in mind that scripts directly deployed in the page source code load synchronously. That means they load in sequence, one after the other. Google Tag Manager, for example, still needs to load all the tags individually, however, it follows an asynchronous methodology – it doesn’t wait for a specific script to load the next one in the page because the main script (Tag Manager) was already loaded. In the end, this results in less impact on the overall page load.

If you use this direct deployment method for other types of tracking codes such as user behaviour, promotion, purchase discount, etc., your website will end up loading more scripts then selling your service, and we all know what happens with users if a page takes too long to load – they leave. Not to mention, for many companies, any updates in a website require a ticket to be opened with the IT team who will, eventually, implement that tag in the page(s). From a marketing perspective, this wait time is extremely frustrating. But marketers are not the only ones who benefit from the use of a Tag Manager, the IT department should own some part in this process. Usually, a new tag implementation is considered by the IT team as a new request they have to implement. A ticket needs to be opened, assigned to a team member, and a time scheduled to start the work. A TMS reduces this process, letting the IT team focus on other tasks.

With a TMS tool, the only script you will have to load is the Tag Manager itself. Everything else is loaded inside it, increasing website performance (customer advantage), providing your company with the centralization of tags (scripts), minimizing the IT dependence, further implementation of variables to collect more data, and access to tag libraries from vendors. These are just a few of many advantages, and that is only talking about client-side tag loading.

There’s more! Server-Side tagging – BETA

Google recently released Server-side tagging which allows Tag Manager users to move measurements tag instrumentation out of their website or app and into server-side processing via Google Cloud. Server-side tagging offers a few advantages over client-side tags:

  • Improved performance: Fewer measurement tags in website or app means less code to run client-side.
  • Better security: Visitor data is protected by collecting and distributing data in a customer-managed, server-side environment. Data is sent to a Google Cloud instance where it is then processed and routed by other tags.

Think of server-side tagging as it’s own bubble of information before the data is sent to Google Analytics (GA). Here, it is possible to clean URLs with PII before sending to GA for example.

A typical tagging configuration without server-side tagging relies on a container in the page to send measurement data to various collection servers. On the other hand, a server container doesn’t run in the user’s browser or on their phone. Instead, it runs on a server that you control.

The server runs in your own Google Cloud Platform project, and only you have access to the data in the server until you choose to send it elsewhere. That means full control over how the data is shaped, and where it goes from the server.

Tag Management Suggestion – Why not Google Tag Manager?

I had the opportunity to work with almost all of the tools mentioned above and read a good amount of documentation to understand them. Personally, and based on experience, I’m very fond of Google Tag Manager. Here are some reasons that may help you answer questions like “Why is Google Tag Manager used?” or “What does Google Tag Manager do?”

Who uses GTM?

Based on calculations I’ve made, GTM is used on around 93% of US websites. Compared to the other tools, this is a great number that has resulted in a lot of people testing new and current features of the tool. This leads to huge communities, forums, questions and answers, and general knowledge about Google Tag Manager.

Also, it’s a Google tool with a dedicated development team behind it updating and fixing problems, not only to make sure everything is working properly but also to bring new ways to connect the data with other Google Marketing Products.

For example, Airbnb was able to improve vendor data collection to 90% with Google Tag Manager. Implementing GTM alongside a well structured Data Layer, they cut tag deployment from days to mere hours, increased site speed, implemented faster launches of new programs, tools, and vendors, gathered more accurate data, better optimizations, and better ROI.

Is Google Tag Manager a stand alone tool?

When looking into a TMS, it’s important to keep in mind the whole architecture of your data. Having a Tag Management System in place is only one piece of the puzzle. Where are you sending that data? Is the tool receiving the data actually receiving everything? What if I want to expand and have a more in-depth analysis of my data? Bring in other tools to better understand my users?

Google Marketing Platform can meet all of these requirements. Here’s a visualization of the Platforms involved:

Source: Google Images

For example, you can use Google Tag Manager to deploy tags and track events on your website and send that information to Google Analytics. Google Analytics, holding that data, can share the same type of information across the other tools. If you want to have an A/B test, you can link Optimize 360 and start using the Goals and Audiences from GA 360, built with the data collected from GTM.

Rituals, a body, home, gifting brand popular in Europe, wanted to reach a wider group of people worldwide who would be truly interested in its products. This could be achieved by building new audiences to reach more users, however, manually doing so was taking too much time.

To solve this issue, Rituals used GMP to create and reach audiences in a scalable way. They not only saved time, but also increased sales by 85%.

Why should I use Google Tag Manager?

One of many reasons you should use GTM is Seamless Integration. Depending on the tool you use, it can understand the data in a certain way. For example, Google Analytics sessions have an End of Day expiration where Facebook does not. This means while GA understands that if a user opens your site at 11:50 pm on Aug. 1st and leaves at 12:15am on Aug. 2nd, it would count as two sessions. Facebook would consider this a single session with a web session length of 10 minutes. Unfortunately, this situation causes the data integrity to be compromised.

Having the same data modeling provides you with a true data visualization and the same type of information being shared across platforms. On the other hand, if you’re using another type of TMS, it either has an analytics tool embedded or you will be sending the data to a different analytics tool.

Easier Normalization – Why is it important to normalize data?

Having the same data modeling will save your company a lot of time when working on Normalization, the process to remove and avoid redundancy information. The main idea behind this is to maintain the same data structure so each variable has the same understanding between the tools.

Let’s say you have two different Tag Management Systems sending the same information to GA. If each of these tools interprets the data information differently (i.e. Sessions from Facebook and Google Analytics), the normalization process can be more difficult in order to accomplish a single source of true data. The consequence of this is bad business decisions based on dirt data.

Another example of normalization using GTM – and to make our understanding better – is to think about Format Values from your site. Most tagging tools can format and transform the return value of a user-defined web variable. This, while it’s a simple feature, can help normalize values that are sent to your tags and reports, and reduce the need to create contingencies for situations where values need to be consistent. For example, if you have Pants, pants, and PANTS, with GTM you can format all of these to lowercase or uppercase. So, instead of three different values, you will hold all of it like PANTS or pants. The same can be applied to empty variables. If there’s nothing to be passed to a specific variable, by default, some code languages return null or undefined. That can be converted to [not set], for example, for better report visualization.

Unfortunately, having perfect alignment of numbers can be hard to accomplish due to, as mentioned, the tools used can inherit data differently. However, using the same group of tools will likely bring those numbers closer to an ultimate match.


Many people may not have heard about Zones as it’s strictly available only to GTM 360 users. Still, being able to use Zones in your company can save you a lot of time with governance and maintenance only because, with Zones, you can delegate specific teams to take care of a unique part of your site. In other words, it’s a decentralization of tasks without losing the overall control of the containers. If you want to know more about Zones, look for my upcoming article here on the Napkyn blog.


Apart from which tool your company is looking to invest in, having a Tag Management System implemented should be something everyone should consider. Internal and external goals and objectives should be taken into consideration for this selection as well, in order to get what best fits your company. If not, you could end up with a brand new TMS with a huge capability, but only be using 10% of its capacity. In other words, not well invested time or money.

However, if properly studied, having a TMS is a win-win process, not only for the IT department but for the marketing and sales teams and of course the end-users.

Ricardo Cristofolini

Implementation Specialist

I’m passionate about what I do. If you meet my manager or co-workers, they would say I’m a team player, engaged and always excited to learn something new. Like everyone else I have some flaws. However I’m not afraid to work around those to bring the best in myself and for the company.

See more posts from Ricardo