Google Tag Manager allows you to quickly and easily update the configuration and flag values of mobile apps that you have created. Instead of rebuilding and deploying new binaries, you can use the Google Tag Manager interface to change configuration values (for example, timeout, ad position, gameplay dynamics) and turn on flag-enabled features in your mobile apps. Read Google Tag Manager for Mobile Apps, below.
Google Tag Manager is useful for managing configuration values that you want to change in the future, or that can change conditionally. Instead of defining constant values in your application, you can make them dynamic and use Google Tag Manager to manage the rules that govern how these values change. Examples include:
the dimensions and locations of ads served in your application, for example, to change ad banner height based on screen size
user interface settings, for example, based on platform
localized strings determined by device language.
A container in Google Tag Manager holds the macros and rules which govern how the configuration and flag values in your app are set. You manage the container - editing its macros and rules, previewing, testing and publishing new versions of the container - from your Google Tag Manager account.
During app development, you use the Google Tag Manager SDK to associate a container with the app. You also provide a default container to deploy with the app. The default container is used to set default configuration values until the first time a container is downloaded. Once the app has connected to the internet and downloaded a container, it will never use the default container again. Applications periodically check for container updates, typically every 12 hours.