Using the native Firebase SDK

It's possible to use Firebase through the web SDK, built only in JavaScript, or the native SDK, which is built in native code for iOS and Android. The web SDK only provides access to some Firebase features and the most notable limitation is the lack of support for browser features used in Firebase Analytics or the redirect URI scheme used for phone authentication. If this is important for you, it may make sense to install the native SDK in your app.

Create Firebase project

If you have not done so already, create a Firebase project for your app by clicking on Add project in the Firebase Console.

This will guide you through a series of steps to create your own Firebase project.

Managed Workflow Setup

Some (but not all) native Firebase features can be used with the Managed Workflow. The most notable native feature is Firebase Analytics, which is otherwise unavailable in react-native using the Firebase JavaScript SDK.

Android

Open Project overview in the firebase console and click on the Android icon or + button to Add Firebase to your Android app.
Make sure that the Android package name is the same as the value of android.package in your app.json.
Register the app & download the config file by clicking "Download google-services.json" and drag the file into your Expo project folder.
Add the relative path to the Android google-services.json file to app.json.

{
  "expo": {
    "android": {
      "package": "com.mypackage.coolapp",
      "googleServicesFile": "./google-services.json"
    }
  }
}

iOS

Open Project overview in the Firebase console and click on the iOS icon or + button to Add Firebase to your iOS app.
Make sure that the iOS bundle ID is the same as the value of ios.bundleIdentifier in your app.json.
Register the app & download the config file by clicking "Download GoogleService-Info.plist" and drag the file into your Expo project folder.
Add the relative path to the iOS GoogleService-Info.plist file to app.json.

{
  "expo": {
    "ios": {
      "bundleIdentifier": "com.mypackage.coolapp",
      "googleServicesFile": "./GoogleService-Info.plist"
    }
  }
}

Web

Open Project overview in the Firebase console and click on the Web icon or + button to Add Firebase to your Web app.
Register the app & copy the config into your app.json under the key web.config.firebase.

{
  "expo": {
    "web": {
      "config": {
        "firebase": {
          "appId": "xxxxxxxxxxxxx:web:xxxxxxxxxxxxxxxx",
          "apiKey": "AIzaXXXXXXXX-xxxxxxxxxxxxxxxxxxx",
          "projectId": "my-awesome-project-id",
          ...
          "measurementId": "G-XXXXXXXXXXXX"
        }
      }
    }
  }
}

Bare Workflow Setup

In the bare workflow, the firebase configuration needs to be added according to the native Firebase SDK installation guides for iOS and Android. Below you will find a tailored instruction for use with react-native and the Expo Bare Workflow.

You are free to use any native Firebase packages such as react-native-firebase in the bare workflow.

Android

Open Project overview in the Firebase console and click on the Android icon or + button to Add Firebase to your Android app.
Make sure that the Android package name is the same as the value of applicationId in your android/app/build.gradle.
Register the app & download the config file by clicking "Download google-services.json" to this location /android/app/google-services.json.

Import the google-services plugin inside of your android/build.gradle file:

buildscript {
    dependencies {
        classpath 'com.google.gms:google-services:4.3.5'
    }
}

Apply the plugin by adding this line to the bottom of the android/app/build.gradle file:

apply plugin: 'com.google.gms.google-services'

Finally rebuild your native Android app: expo run:android

iOS

Open Project overview in the Firebase console and click on the iOS icon or + button to Add Firebase to your iOS app.
Make sure that the iOS bundle ID is the same as the value of Bundle Identifier of your iOS project.
Register the app & download the config file by clicking "Download GoogleService-Info.plist".
Open your Expo iOS project in Xcode ios/{projectName}.xcworkspace and then drag the services file into your project. If you don't see the .xcworkspace workspace file, run npx pod-install to create it.
- Be sure to enable 'Copy items if needed'.
Initialize the default Firebase app by opening the AppDelegate file in your project ios/{projectName}/AppDelegate.m.
At the top of the file:
```
@import Firebase;
```

At the top of the didFinishLaunchingWithOptions method:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [FIRApp configure];

Rebuild your iOS project to see the changes: expo run:ios

Usage with react-native-firebase

After following the iOS and Android setup, you can optionally configure your project to work with react-native-firebase version 6 as well.

Install the react-native-firebase packages (e.g. yarn add @react-native-firebase/app @react-native-firebase/auth etc..)
Install the pods on iOS

Continue further on the react-native-firebase website.