Tag Manager overview
Google Tag Manager is a tag management system that allows you to quickly and easily update tracking codes and related code fragments collectively known as "tags" on your website or mobile app. Once a small segment of Tag Manager code has been added to your project, you can easily configure and deploy your tag configurations from a web-based user interface without the need to deploy additional code in most cases. This reduces errors and frees you from having to involve a developer every time you need to make changes.
When Tag Manager is installed, your website or app will be able to communicate with the Tag Manager servers. You can then use Tag Manager's web-based user interface to set up tracking tags, establish triggers that cause your tag to fire when certain events occur, and create variables that can be used to simplify and automate your tag configurations.
A collection of tags, triggers, variables, and related configurations installed on a given website or mobile app is called a container. A Tag Manager container can replace all other manually-coded tags on a site or app, including tags from Google Ads, Google Analytics, Floodlight, and 3rd party tags.
When you upgrade your site or app to Tag Manager, the best practice is to migrate all your tags at once. However, this is not a mandatory requirement. Tag Manager can fire your migrated tags alongside any tags that are not administered through Tag Manager.
Your Tag Manager account allows you to administer the tags for one or more websites or mobile apps. Although you can set up multiple Tag Manager accounts from a single Google account, you’ll typically only need one Tag Manager account per company or organization. Learn more.