Firebase Google Login on iOS

Introduction

This guide will help you integrate Google Sign-In with Firebase Authentication on iOS. I assume you have already completed the general Firebase Google setup.

Note

I will assume that you have not yet created your iOS app in the Firebase Console. If you have, your steps will be slightly different.

Setup Steps

1. Go to your project overview over at console.cloud.google.com

   

2. Click on the Add app button

   

   Note

   It is possible that you will have to look here for this button. This applies only if you have already created a different app in the Firebase Console.

   

3. Select iOS

   

4. Fill the first part of the form

   1. Fill the Apple bundle ID
      1. Open Xcode at your app using npx cap open ios
      2. Double click on App
      3. Ensure that you are on Targets -> App
      4. Find your Bundle Identifier

         Note

         The ID shown here will differ from the one I will use for the rest of the guide. I will use app.capgo.plugin.SocialLogin for the rest of the guide.

      5. Copy the Bundle Identifier and paste it in the Firebase console
   2. Click on the Register app button

5. Skip the Download config file step

   

6. Skip the Add firebase SDK step

   

7. Skip the Add initialization code step

   

8. Click on the Continue to console button

   

9. Get your iOS client ID and your YOUR_DOT_REVERSED_IOS_CLIENT_ID

   1. Go to Google Cloud Console at console.cloud.google.com

   2. Find your project

      1. Click on the project selector
      2. Search up your project by the exact name of your Firebase project and click on it. In my case, it is sociallogin-tutorial-app.

   3. Open the search bar and open credentials

      1. Open the search bar
      2. Search for credentials and click on the APIs and Services one (number 2 on the screenshot)

   4. Click on the iOS client for [YOUR_APP_ID] (auto created by Google Service) one. In my case, it is sociallogin-tutorial-app.

      

   5. Copy the Client ID as well as the iOS URL scheme. This will be respectively your iOSClientId and YOUR_DOT_REVERSED_IOS_CLIENT_ID.

      Note

      You will pass the iOSClientId in the initialize method of the plugin, while you will use the YOUR_DOT_REVERSED_IOS_CLIENT_ID in the Info.plist file of your app, as explained in the next part of this guide.

      

10. Get your web client ID

    1. Go back to the Firebase console and go to Build -> Authentication
    2. Click on the Sign-in method button
    3. Click on the Google provider
    4. Click on the Web SDK configuration button
    5. Copy the Web client ID. This will be your webClientId in the initialize method of the plugin.

11. Modify your app’s Info.plist

    1. Open Xcode and find the Info.plist file

       

    2. Right click this file and open it as source code

       

    3. At the bottom of your Plist file, you will see a </dict> tag

       

    4. Insert the following fragment just before the closing </dict> tag

       

       <key>CFBundleURLTypes</key>
       <array>
       <dict>
         <key>CFBundleURLSchemes</key>
         <array>
           <string>YOUR_DOT_REVERSED_IOS_CLIENT_ID</string>
         </array>
       </dict>
       </array>
       <key>GIDClientID</key>
       <string>YOUR_IOS_CLIENT_ID.apps.googleusercontent.com</string>

    5. Change the YOUR_DOT_REVERSED_IOS_CLIENT_ID to the value copied in step 9 (the iOS URL scheme)

       

       Caution

       Ensure that this value STARTS with com.googleusercontent.apps

12. Change the YOUR_IOS_CLIENT_ID to the iOS Client ID you copied in step 9

13. Save the file with Command + S

14. Modify the AppDelegate.swift

    1. Open the AppDelegate

       

    2. Insert import GoogleSignIn at the top of the file

       

    3. Find the func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey: Any] = [:]) function

       

    4. Modify the function to look like this

       func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey: Any] = [:]) -> Bool {
           // Called when the app was launched with a url. Feel free to add additional processing here,
           // but if you want the App API to support tracking app url opens, make sure to keep this call
       
           var handled: Bool
       
           handled = GIDSignIn.sharedInstance.handle(url)
           if handled {
             return true
           }
       
           return ApplicationDelegateProxy.shared.application(app, open: url, options: options)
       }

       

    5. Save the file with Command + S

15. Using the Google login in your app

    At this step, you are ready to use the Google login in your app. Please use the authUtils.ts file of the example app to authenticate with Google.

The user will be automatically created in Firebase Auth on first sign-in

Troubleshooting

If authentication hangs or fails:

• Verify the idToken audience matches your Firebase web client ID
• Check that Google Sign-In is enabled in Firebase Console
• Ensure Info.plist has the correct URL schemes and GIDClientID
• Verify iOSServerClientId matches your web client ID
• Review the example app code for reference