Google Analytics collects usage and behavior data for your web app. The SDK logs two primary types of information:
Events: What is happening in your app, such as user actions, system events, or errors.
User properties: Attributes you define to describe segments of your user base, such as language preference or geographic location.
Before you begin
If you're creating a new Firebase project, enable Google Analytics during the project creation workflow.
If you're using an existing Firebase project that doesn't have Google Analytics enabled, go to the Integrations tab of your
to enable it. > Project settings
When you enable Google Analytics in your project, your Firebase web apps are linked to Google Analytics data streams associated with an App + Web property.
Add the Analytics SDK to your app
Depending on how your web application is hosted, your configuration may be handled automatically or you may need to update your Firebase configuration object. If your web app already uses Google Analytics, you may need to do additional setup described in Use Firebase with existing gtag.js tagging.
Check that your Firebase config object in your code contains
measurementId. This ID is automatically created when you enable Analytics in your Firebase project and register a web app, and it's required to use Analytics.
If your app uses Firebase Hosting and uses reserved URLs for the Firebase SDKs:
Firebase automatically handles configuring your application. To complete setup, add the scripts from the Your apps card in your Project settings to the <body> tag of your app, if you haven't already.
If your app does not use reserved URLs: If you're working with an existing web app, update the Firebase config object in your code to ensure the
measurementIdfield is present. The config object should look similar to the following example:
Initialize Firebase Analytics:
const analytics = firebase.analytics();
Use Firebase with existing gtag.js tagging
If you previously had Google Analytics running in your app using the gtag.js snippet, your app may require additional setup if you plan to do one of the following:
- Add Google Analytics calls from Firebase to the page but also plan to
gtag()calls directly on the same page.
- Want to use the same measurement ID between both direct
gtag()calls and Google Analytics data sent to Firebase.
To ensure your events are available for use by all Firebase services, complete the following additional setup steps:
[?id=GA_MEASUREMENT_ID](https://www.googletagmanager.com/gtag/js?id=GA_MEASUREMENT_ID)in the url. Your gtag snippet should be similar to
<script async src="https://www.googletagmanager.com/gtag/js"></script>
Remove the line
gtag('config', 'GA_MEASUREMENT_ID');where the
GA_MEASUREMENT_IDis the same as the
measurementIdin your Firebase config snippet. If you have other IDs for other Analytics properties on the page, you do not need to remove their config line.
Make sure you call
firebase.analytics()before you send any events with
Otherwise, events sent to that ID with
gtag() calls will not be associated
with Firebase and will not be available for targeting in other
Start logging events
Certain events are recommended for all apps; others are recommended for specific business types or verticals. You should send suggested events along with their prescribed parameters, to ensure maximum available detail in your reports and to benefit from future features and integrations as they become available. This section demonstrates logging a pre-defined event, for more information on logging events, see Log events.
The following example demonstrates how to log a recommended event to indicate a user has received a notificationt in your app: