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
- Install the Firebase SDK.
- Add your app to your Firebase project in the Firebase console.
Create a Database
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.
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.
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.
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.Click Done.
When you enable Realtime Database, it also enables the API in the Cloud API Manager.
Add Firebase Realtime Database to your app
Add the dependency for Firebase Realtime Database to your project's
Podfile
:pod 'Firebase/Database'
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.
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.
- Import the Firebase module in your
UIApplicationDelegate
:Swift
import Firebase
Objective-C
@import Firebase;
- Configure a
FirebaseApp
shared instance, typically in your app'sapplication: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.
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.
Prepare to launch your app:
- 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.