This time the guide will be indeed shorter than usual. First of all, this blog post will not talk about multiple GTM containers on the same page. I’m answering a bit different question.
Say, you have 3 websites. How many GTM containers do you need here? One? Two? Three?
The reality is that there is no universal answer. One container might work, two or three containers might do the job as well. The real answer is: it depends.
Think about the websites first
When it comes to deciding the number of containers, I always think of the structure of websites.
Are those 3 (or insert any other numbers) websites very similar (regarding content, structure, etc.)? Or are they quite different?
- If you have three websites that are very similar and, say, the main difference is localization (language), then I’d recommend using the same GTM container on all three websites. Because, most likely, you’ll be tracking the same things on all websites.
- If you have three websites that are totally different in terms of their content, structure, functionality, e.g. an online store, a blog, and a support page, I’d recommend using separate containers for each website because (probably) each one of them will have pretty unique tags, triggers, and variables.
Several different websites
By using the same GTM container on several different websites, your trigger conditions will contain more rules, more exceptions. It will be more cumbersome to ensure that a particular tag fires only on one website (e.g. only in your online store) and not the others. Your list of tags, triggers, and variables will grow faster and soon will become more complex to manage.
Eventually, the container might even exceed its maximum size and you will be forced to either get rid of some items or migrate to separate containers.
By using separate GTM containers, you’ll notice the smoother tag management process. There will be fewer tags/triggers/variables, triggers will be less complex (with fewer conditions and exceptions). It will be easier for you to find particular container elements (rather than browse hundreds of entities).
If there are more differences than common things between tracking implementations of each website, you should go with separate containers for each site.
Several similar websites
On the other hand, I don’t always recommend having separate GTM containers. What if the websites are pretty similar? Here’s what the process looks like if you each website has its own GTM container (even though they all are being tracked with the same Google Analytics Property, same Facebook Pixel, etc.):
- You configure particular changes in container A.
- Then you need to copy the same changes to containers B and C. You can try to do that manually (oh no!), export a part of the container with gtmtools.com or use the GTM Copy/Paste extension.
- And this will happen every time you implement a change. Far from an efficient and agile work process!
But if you had one GTM container across all three websites, one single change would be applied to all three websites instantly.
Of course, sometimes you will want to fire a tag only on one website but the scale of such “unique” tracking implementations will probably be pretty low.
To sum up, every time you face the situation with several websites and you need to decide how many GTM containers are needed, think of how different/similar those websites are.
What kind of tracking are you planning to implement on those sites? Will tags/triggers/variables be quite similar on all three websites? Or, contrary, quite unique for each one of them?
- If those websites are quite different in structure/functionality and you plan to track different things on each one of them (e.g. Enhanced E-commerce is planned only for an online store), then you should go with separate GTM container for each site.
- On the other hand, if those websites are quite similar and you plan to track the same things across all of them, it will be easier to utilize a single container (because all the changes will be immediately applied everywhere).