Installation & Setup on iOS

The Firebase Realtime Database is a cloud-hosted database. Data is stored as JSON and synchronized in realtime to every connected client. When you build cross-platform apps with our Android, iOS, and JavaScript SDKs, all of your clients share one Realtime Database instance and automatically receive updates with the newest data.

Prerequisites

1. Install the Firebase SDK.
2. Add your app to your Firebase project in the Firebase console.

Create a Database

1. Navigate to the Realtime Database section of the Firebase console. You'll be prompted to select an existing Firebase project. Follow the database creation workflow.

2. Select a starting mode for your Firebase Security Rules:

   Test mode

   Good for getting started with the mobile and web client libraries, but allows anyone to read and overwrite your data. After testing, make sure to review the Understand Firebase Realtime Database Rules section.

   Note: If you create a database in Test mode and make no changes to the default world-readable and world-writeable Rules within a trial period, you will be alerted by email, then your database rules will deny all requests. Note the expiration date during the Firebase console setup flow.

   To get started with the web, iOS, or Android SDK, select test mode.

   Locked mode

   Denies all reads and writes from mobile and web clients. Your authenticated application servers can still access your database.

3. Choose a region for the database. Depending on your choice of region, the database namespace will be of the form <databaseName>.firebaseio.com or <databaseName>.<region>.firebasedatabase.app. For more information, see select locations for your project.

4. Click Done.

When you enable Realtime Database, it also enables the API in the Cloud API Manager.

Add Firebase Realtime Database to your app

Note: We recommend using CocoaPods to install the Firebase libraries. If you set up Firebase using Swift Package Manager, you can skip CocoaPods-related steps like modifying Podfiles and running the pod command.

1. Add the dependency for Firebase Realtime Database to your project's Podfile:

   pod 'Firebase/Database'
   

2. Run pod install and open the created .xcworkspace file.

Configure Realtime Database Rules

The Realtime Database provides a declarative rules language that allows you to define how your data should be structured, how it should be indexed, and when your data can be read from and written to.

Note: By default, read and write access to your database 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 your database open to anyone, even people not using your app, so be sure to restrict your database again when you set up authentication.

Set up Firebase Realtime Database

You must initialize Firebase before any Firebase app reference is created or used. If you have already done this for another Firebase feature, you can skip this step.

1. Import the Firebase module in your UIApplicationDelegate:

   Swift

   import Firebase

   Objective-C

   @import Firebase;

2. Configure a FirebaseApp shared instance, typically in your app's application:didFinishLaunchingWithOptions: method:

   Swift

   // Use Firebase library to configure APIs
   FirebaseApp.configure()

   Objective-C

   // Use Firebase library to configure APIs
   [FIRApp configure];

Then, create a reference to your database and specify the location you want to write to.

Note: To get a reference to a database other than a us-central1 default dstabase, you must pass the database URL to database() (or Objective-C databaseWithURL). For a us-central1 default database, you can call database() (or database) without arguments.

You can find your Realtime Database URL in the Realtime Database section of the Firebase console. It will have the form https://<databaseName>.firebaseio.com (for us-central1 databases) or https://<databaseName>.<region>.firebasedatabase.app (for databases in all other locations).

Swift

var ref: DatabaseReference!

ref = Database.database().reference()

Objective-C

@property (strong, nonatomic) FIRDatabaseReference *ref;

self.ref = [[FIRDatabase database] reference];

Next Steps

• Learn how to structure data for Realtime Database.

• Scale your data across multiple database instances.

• Read and write data.

• View your database in the Firebase console.

• Prepare to launch your app:

  • Enable App Check to help ensure that only your apps can access your databases.

  • Set up budget alerts for your project in the Google Cloud Console.

  • Monitor the Usage and billing dashboard in the Firebase console to get an overall picture of your project's usage across multiple Firebase services. You can also visit the Realtime Database Usage dashboard for more detailed usage information.

  • Review the Firebase launch checklist.