GTM Changes Highlights - May 2026

Google has informed the industry that we're going to see some significant changes in Google Tag Manager and Google Tags this summer. In addition to what's coming up in Google Marketing Live, here's a little more colour to help you see the direction of travel.

May 2026 - UI Refresh

No functionality is being removed, but you'll see an easier to use interface - more than just a welcome refresh. The UI hasn't seen any significant change for a couple of years so this will be pleasing to many.

Container Overview

Starting with the Container Overview - a little different already. See data destinations clearly - and it's interactive - lot's of deeply linked treasure is much nearer the surface for fast, easy access:

Essential Tag Settings in GTM

For example, all the key settings related to the Google Tag config will be available in the GTM menu - no need to configure in GA, when you can easily access them in GTM.

Be aware, this underlines the importance of access governance. Be absolutely certain who can access, and change your settings in this area.

Something super-cool about this change though - you can test these changes in a workspace. These changes (IMHO) are much more easily audited when ring-fenced in a discrete workspace:

That's just an example changer above - I do not endorse this change! I backed out of it immediately. You know what I would recommend? Tie down GA admin access as far as you can. Enable Tag Settigns change through GTM only (as far as possible) and turn your governance over Google Tag Settings up to 11 - I repeat: GTM only.

Preview Mode FTW

You'll see a lot more detail and context in the preview mode panel. Access to the automatic event detection and User Provided Data (UPD) capabilities during debug will go a long way to clarifying what data is collected, when, and by what:

Controlling UPD is a key ingredient to the hot topic of Data Strength - the phrase "doubling down" comes to mind.

In addition, expect to see fine grained detail on the hits being sent from the container - more visibility, more control, better data collection.

Summer 2026:

Google Tags -> Containers -> Google Tags

For those readers in the UK, "summer" is a period of time during which the grey sky has a slightly brighter grey hue, humidity sky rockets, and the London Underground attempts to simultaneously bake and steam you.

To bring you some cheer during the drought/monsoon season, welcome the simplification of the relationship between GTM Containers and Google Tags.

Flippancy aside, these are fundamental changes for good. Google Tag configuration is easy to do, but hard to do really well. This means it's surprisingly easy to break. This results in very common Unassigned in attribution reports, and (not set) landing pages and source / medium values.

1: Google Tags get Tag Manager capabilities:

This means gtag only sites get preview mode and version control - yay!

2: Visual Event Builder

This is an exciting development that's going to have a positive impact on measurement time-to-market. Just walk through the site to conversion and GTM builds the tags, triggers, and variables for you!

Our advice, use it, test it, and keep a human in the loop. Make sure whatever is automatically produced aligns with your standards and conventions.

3: Container Optimisation (this is a BIG THING)

Tag Manager containers will be able to send data directly to destinations - no need to load a Google Tag first! This has positive impact on site performance and data quality.

Slick Migration, Easy back-out - but use caution

The Container Optimisation requires a manual step to upgrade the container.

In testing, we saw a pretty faultless process to migrate to the new UI, and tested backing out of the change too. No brainer - worked just as expected. What's really neat is that the change is ring-fenced in a workspace.

This means you can spin up a new workspace to test the change quite easily.

The end result is a direct connection between the container and destination - improved data quality - but exactly how?

What does it mean for your data?

Expect fewer (not set) issues. Easier to manage GTM containers means fewer maintenance issues.

Less complexity, generally means better understanding, and more trust.

The journey builder will shorten time to market. It will emphasise doing it right, and making sure triggers are done properly.

What do you need to do now?

Preparation for feature adoption is the first part of change management. Assess campaign/trading peaks and make sure the summer changes don't impact BAU.

As the feaures become available, test carefully. Don't blindly accept the changes. We can help you plan, test, execute, and measure the impact of these changes.

Rigorous processes will make sure any data improvements are reliable, consistent, and understood - essential for trust in data, and a win for data strength.