This page provides general, high-level best practices for setting up Firebase projects and registering your apps with a project so that you have a clear development workflow using distinct environments. Once you're familiar with the best practices on this page, check out our general security guidelines.
Understanding the hierarchy of Firebase projects
This diagram shows the basic hierarchy of a Firebase project. Here are the key relationships:
A Firebase project is like a container for all your apps and any resources and services provisioned for the project.
A Firebase project can have one or more Firebase Apps registered to it (for example, both the iOS and Android versions of an app, or both the free and paid versions of an app).
All Firebase Apps registered to the same Firebase project share and have access to all the same resources and services provisioned for the project. Here are some examples:
All the Firebase Apps registered to the same Firebase project share the same backends, like Firebase Hosting, Authentication, Realtime Database, Cloud Firestore, Cloud Storage, and Cloud Functions.
All Firebase Apps registered to the same Firebase project are associated with the same Google Analytics property, where each Firebase App is a separate data stream in that property.
Where does a Google Cloud project fit into this hierarchy?
One aspect of the Firebase project hierarchy that's not shown in the diagram above is the relationship with a Google Cloud project. A Firebase project is actually just a Google Cloud project that has additional Firebase-specific configurations and services enabled for it. Note that all the apps registered to the same Firebase project also share and have access to all the same Google Cloud resources and services, too.
Learn more about the Firebase and Google Cloud relationship in Understand Firebase projects
Registering app variants with Firebase projects
Here are some important tips for registering your app variants with a Firebase project:
Ensure that all apps registered to a Firebase project are platform variants of the same application from an end-user perspective. Register the iOS, Android, and web versions of the same app or game with the same Firebase project.
If you have multiple build variants that could share the same Firebase resources, register the variants with the same Firebase project. Some examples are a blog and a web app in the same project, or both the free and paid versions of the same app in the same project.
If you have multiple build variants that are based on release status (rather than on common end-user activity or access, like above), register each variant with a separate Firebase project. An example is your debug vs release build – register each of these builds in its own Firebase project.
Builds based on release status should not share the same Firebase resources because that risks your debug data polluting or even overriding your prod data.
The platform-variants of each of these build variants should be in the same Firebase project. For example, register both the iOS and the Android debug builds in a "dev" Firebase project because they can both interact with the same non-prod data and resources.
Multi-tenancy can lead to serious configuration and data privacy concerns, including unintended issues with analytics aggregation, shared authentication, overly-complex database structures, and difficulties with security rules.
Generally, if a set of apps don't share the same data and configurations, strongly consider registering each app with a different Firebase project.
For example, if you develop a white-label application, each independently labeled app should have its own Firebase project, and the iOS and Android versions of that label should be in the same Firebase project. Each independently labeled app shouldn't (for privacy reasons) share data with the others.
Review the general security guidelines for different environments. You want to make sure each environment and its data are secure.
Review the Firebase launch checklist.