In most organisations it is common practice to utilise different environments for development, test and UAT. The environments are used to validate new code at varying stages of the web development process, including building an analytics measurement strategy.
A common issue I find in GA is one that the main or production tag is used on all domains including those used for testing. As a result traffic and conversion metrics including sales revenue can be polluted by test activity making the analytics data inaccurate.
In this post I want highlight a simple mechanism within GTM to easily manage this and avoid the issue.