Overview

To use measurement and advertising products such as Google Analytics, Ads conversion measurement, remarketing, and more, you add Google tags to your website. You can write tags in JavaScript, using the global site tag, or add them with configuration, using the graphical Google Tag Manager user interface. Tag Manager supports both websites and mobile apps. If you use Firebase to build mobile apps, an API is available to provide the required information to Google measurement and advertising products.

What is a "tag"?

Tags in the digital marketing and analytics context are similar to, but distinct from, the standard HTML tags that developers use to code web pages. The analytics version of the word "tag" is derived from the fact that the tags provided by vendors are often encapsulated by HTML <script> or <img> tags.

In the context of Google documentation, tags are segments of code that track user behavior such as time on page, clicks, and purchases. They often do so, for example by saving or reading browser cookies.

You enable Google products and features with Google tags. Analytics, marketing, and support vendors provide third-party tags for integrating their products into websites and mobile apps.

What is the global site tag?

The global site tag is a code snippet where you use the (gtag.js) JavaScript tagging library to send measurement data and advertising features to Google products, including Google Ads, Campaign Manager 360, Display & Video 360, Search Ads 360, Google Analytics, and more. The global site tag allows you to use the same JavaScript library to interact with most of Google's measurement products in a single code snippet on each of your website pages.

What is Google Tag Manager?

Tag Manager is a tag management system that lets you configure and instantly deploy tag code on your website or mobile app from an easy to use web-based user interface. You do not need to be a JavaScript developer to use Tag Manager.

In addition to support for Google product tags, Tag Manager features support for third-party tags, organization features, version control, and enterprise collaboration and security features.

In Google documentation, global site tag examples consist of gtag.js code, while Tag Manager examples provide the steps necessary to configure tags.

Usage example

The following example illustrates the difference between use of the global site tag and Tag Manager. This global site tag shows a snippet that you could add to each page of your website to enable Google Analytics:

<script async
  src="https://www.googletagmanager.com/gtag/js?id=GA_TRACKING_ID">
</script>

<script>
  window.dataLayer = window.dataLayer || [] ;
  function gtag(){dataLayer.push(arguments);}
  gtag( 'js', new Date () ) ;

  gtag( 'config', 'GA_TRACKING_ID');
</script>

Then to enable conversion tracking for Google Ads, add the following in the global site tag on each page: gtag( 'config', 'AW- CONVERSION_ID');:

<script async
  src="https://www.googletagmanager.com/gtag/js?id=GA_TRACKING_ID">
</script>

<script>
  window.dataLayer = window.dataLayer || [] ;
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date ()) ;

  gtag('config', 'GA_TRACKING_ID');
  gtag('config', 'AW- CONVERSION_ID');
</script>

To use Tag Manager to enable measurement of ads conversions, you can enable the same functionality as the above example by configuring a tag in the Tag Manager user interface and publishing it with one click to all pages of a website. See Google Ads conversions to learn more.

Tags supported by global site tag and Tag Manager

Global site tag and Tag Manager provide the following tag support:

Tag Type	gtag.js	Tag Manager
Google Analytics 4	Yes	Yes
Google Analytics: Universal Analytics	Yes	Yes
Google Ads Conversions	Yes	Yes
Google Ads Remarketing	Yes	Yes
Floodlight	Yes	Yes
Google Optimize	Yes	Yes
Google Surveys Website Satisfaction	No	Yes
Third-party tags	No	Yes

In addition to the Google measurement products listed here, Tag Manager supports a wide variety of third-party tags. The Community Template Gallery contains additional tag and variable templates maintained by third parties. You can also create and share your own tags with custom templates.

To tag a website with a supported Google product, we recommend using either the global site tag library or the Tag Manager. To learn more about choosing the right option, read "Google Tag Manager, global site tags, or Firebase?".

• Learn more about the global site tag
• Install the global site tag
• Learn more about Tag Manager
• Install Tag Manager