Integrate GTM Correctly
At this moment Google Tag Manager does not work well with A/B testing software, as you can see in the limited explanation on their GTM feature page. Google Tag Manager loads scripts in an asynch way, delaying the load of tags that need to load before anything else (this is the case with Convert's tags and in fact any other tags that needs to modify the page, without a blinking effect).
Though currently there is support for document.write function inside Google Tag Manager (GTM), that still does not offer the same capabilities of the native "document.write". This new rendering engine is just basically allowing a document.write like function to work in a asynch environment; but A/B testing tags need exactly the opposite: to be loaded in a synchronized way
Even though loading Convert Experiments code through Google Tag Manager will somewhat work (not totally) we do not recommend it since the experience is sub optimal. As soon as Google TagManager offer this feature we will update this document.
So again what works and what does not work in GTM?
- Yes, you can add an A/B testing tool to Google Tag Manager (GTM).
No this is not a great experience since your test variation will load after the page was fully loaded and will most likely lead to blinking (seeing the original page and after that the test variation)
- Yes, Google Tag Manager has a document.write feature so we can run an A/B testing tool?
No, this document.write is not the "real" thing so again A/B testing tools have problems.
- Other A/B testing tools say they work with Google Tag Manager.
Same problems there, maybe less open about the consequences, but give it a try.
- Yes, revenue tracking might work in Google Tag Manager.