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

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

Add Firebase Realtime Database to your app

Ensure the following dependencies are in your project's Podfile:

pod 'Firebase/Analytics'
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. 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.

Import the Firebase module in your UIApplicationDelegate:
Swift
```
import Firebase
```
Objective-C
```
@import Firebase;
```
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];
```

Once you've initialized Firebase Realtime Database, define and create a reference to your database as follows:

Swift

var ref: DatabaseReference!

ref = Database.database().reference()

Objective-C

@property (strong, nonatomic) FIRDatabaseReference *ref;

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

Prepare for Launch

Before launching your app, we recommend walking through our launch checklist to make sure your app is ready to go!

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.