Get started with Cloud Storage on Android

Cloud Storage for Firebase lets you upload and share user generated content, such as images and video, which allows you to build rich media content into your apps. Your data is stored in a Google Cloud Storage bucket — an exabyte scale object storage solution with high availability and global redundancy. Cloud Storage for Firebase lets you securely upload these files directly from mobile devices and web browsers, handling spotty networks with ease.

Before you begin

  1. If you haven't already, make sure you've completed the getting started guide for Android apps. This includes:

    • Creating a Firebase project.

    • Registering your Android app with the project, and connecting your app to Firebase by adding the Firebase dependencies, the Google services plugin, and your Firebase config file (google-services.json) to your app.

  2. Make sure your Firebase project is on the pay-as-you-go Blaze pricing plan. If you're new to Firebase and Google Cloud, check if you're eligible for a $300 credit.

Create a default Cloud Storage bucket

  1. From the navigation pane of the Firebase console, select Storage.

    If your project is not yet on the pay-as-you-go Blaze pricing plan, then you'll be prompted to upgrade your project.

  2. Click Get started.

  3. Select a location for your default bucket.

  4. Configure the Firebase Security Rules for your default bucket. During development, consider setting up your rules for public access.

  5. Click Done.

You can now view the bucket in the Cloud Storage Files tab of the Firebase console. Your default bucket name format is PROJECT_ID.firebasestorage.app.

Set up public access

Cloud Storage for Firebase provides a declarative rules language that lets you define how your data should be structured, how it should be indexed, and when your data can be read from and written to. By default, read and write access to Cloud Storage is restricted so only authenticated users can read or write data. To get started without setting up Authentication, you can configure your rules for public access.

This does make Cloud Storage open to anyone, even people not using your app, so be sure to restrict your Cloud Storage again when you set up authentication.

Add the Cloud Storage SDK to your app

In your module (app-level) Gradle file (usually <project>/<app-module>/build.gradle.kts or <project>/<app-module>/build.gradle), add the dependency for the Cloud Storage library for Android. We recommend using the Firebase Android BoM to control library versioning. 

dependencies {
    // Import the BoM for the Firebase platform
    implementation(platform("com.google.firebase:firebase-bom:33.5.1"))

    // Add the dependency for the Cloud Storage library
    // When using the BoM, you don't specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-storage")
}

By using the Firebase Android BoM, your app will always use compatible versions of Firebase Android libraries.

(Alternative)  Add Firebase library dependencies without using the BoM

If you choose not to use the Firebase BoM, you must specify each Firebase library version in its dependency line.

Note that if you use multiple Firebase libraries in your app, we strongly recommend using the BoM to manage library versions, which ensures that all versions are compatible. 

dependencies {
    // Add the dependency for the Cloud Storage library
    // When NOT using the BoM, you must specify versions in Firebase library dependencies
    implementation("com.google.firebase:firebase-storage:21.0.1")
}
Looking for a Kotlin-specific library module? Starting in October 2023 (Firebase BoM 32.5.0), both Kotlin and Java developers can depend on the main library module (for details, see the FAQ about this initiative).

Set up Cloud Storage in your app

  1. Make sure the Firebase config file (google-services.json) in your app's codebase is updated with the name of your default Cloud Storage bucket.

    1. Obtain your updated config file..

    2. Use this downloaded config file to replace the existing google-services.json file in your app's module (app-level) directory.

      Make sure that you only have this most recent downloaded config file in your app and that its filename isn't appended with additional characters, like (2).

  2. Access your Cloud Storage bucket by creating an instance of FirebaseStorage:

    Kotlin+KTX 

    storage = Firebase.storage
    StorageActivity.kt
    // Alternatively, explicitly specify the bucket name URL.
// val storage = Firebase.storage("gs://BUCKET_NAME")

    Java 

    FirebaseStorage storage = FirebaseStorage.getInstance();
    StorageActivity.java
    // Alternatively, explicitly specify the bucket name URL.
// FirebaseStorage storage = FirebaseStorage.getInstance("gs://BUCKET_NAME");

You're ready to start using Cloud Storage!

Next step? Learn how to create a Cloud Storage reference.

Advanced setup

There are a few use cases that require additional setup:

The first use case is perfect if you have users across the world, and want to store their data near them. For example, you can create buckets in the US, Europe, and Asia to store data for users in those regions to reduce latency.

The second use case is helpful if you have data with different access patterns. For example: you can set up a multi-regional or regional bucket that stores pictures or other frequently accessed content, and a nearline or coldline bucket that stores user backups or other infrequently accessed content.

In either of these use cases, you'll want to use multiple Cloud Storage buckets.

The third use case is useful if you're building an app, like Google Drive, which lets users have multiple logged in accounts (for instance, a personal account and a work account). You can use a custom Firebase App instance to authenticate each additional account.

Use multiple Cloud Storage buckets

If you want to use a Cloud Storage bucket other than the default bucket described earlier in this guide, or use multiple Cloud Storage buckets in a single app, you can create an instance of FirebaseStorage that references your custom bucket:

Kotlin+KTX 

// Get a non-default Storage bucket
val storage = Firebase.storage("gs://my-custom-bucket")
StorageActivity.kt

Java 

// Get a non-default Storage bucket
FirebaseStorage storage = FirebaseStorage.getInstance("gs://my-custom-bucket");
StorageActivity.java

Working with imported buckets

When importing an existing Cloud Storage bucket into Firebase, you'll have to grant Firebase the ability to access these files using the gsutil tool, included in the Google Cloud SDK:

gsutil -m acl ch -r -u service-PROJECT_NUMBER@gcp-sa-firebasestorage.iam.gserviceaccount.com gs://BUCKET_NAME

You can find your project number as described in the introduction to Firebase projects.

This does not affect newly created buckets, as those have the default access control set to allow Firebase. This is a temporary measure, and will be performed automatically in the future.

Use a custom Firebase App

If you're building a more complicated app using a custom FirebaseApp, you can create an instance of FirebaseStorage initialized with that app:

Kotlin+KTX 

// Get the default bucket from a custom FirebaseApp
val storage = Firebase.storage(customApp!!)

// Get a non-default bucket from a custom FirebaseApp
val customStorage = Firebase.storage(customApp, "gs://my-custom-bucket")
StorageActivity.kt

Java 

// Get the default bucket from a custom FirebaseApp
FirebaseStorage storage = FirebaseStorage.getInstance(customApp);

// Get a non-default bucket from a custom FirebaseApp
FirebaseStorage customStorage = FirebaseStorage.getInstance(customApp, "gs://my-custom-bucket");
StorageActivity.java

Next steps