iOS setup

Config files

OAuth, plist/json downloads, and file paths: Google Cloud & config files.

Quick checklist

Step		Why
iOS OAuth client (bundle ID)	Required	Registers your app with Google
URL scheme (REVERSED_CLIENT_ID)	Required	OAuth redirect must open your app
GoogleService-Info.plist	Required for autoDetect	Supplies WEB_CLIENT_ID to native code
bundle exec pod install --project-directory="ios"	Required	Links GoogleSignIn CocoaPod (from app root)
AppDelegate GIDSignIn.sharedInstance.handle(url)	Optional (Expo) · Recommended (bare RN) · Required (multiple URL handlers or stuck redirect)	Forwards OAuth URL to GIDSignIn; not only for multiple handlers — see AppDelegate
iosClientId in configure()	Optional	Usually inferred from plist

---

OAuth client

Required

Why: iOS sign-in is tied to your bundle identifier. Google issues tokens only for registered iOS clients.

1. Create an iOS OAuth client with your bundle identifier.
2. Download GoogleService-Info.plist or note the iOS client ID and REVERSED_CLIENT_ID.

---

GoogleService-Info.plist

Add plist to Xcode

Required for autoDetect

Why: Native code reads WEB_CLIENT_ID from the plist when webClientId is 'autoDetect'.

Optional for explicit webClientId only

Why optional for client ID: You can pass webClientId in JS. You still need the URL scheme below — the plist is the easiest source for REVERSED_CLIENT_ID.

1. Add GoogleService-Info.plist to your Xcode project (drag into the app target, “Copy items if needed”). Get the file.
2. For webClientId: 'autoDetect', ensure the plist contains WEB_CLIENT_ID (Firebase-linked projects include this).

GoogleOneTapSignIn.configure({ webClientId: 'autoDetect' })

Or pass the Web client ID explicitly:

GoogleOneTapSignIn.configure({
  webClientId: 'YOUR_WEB_CLIENT_ID.apps.googleusercontent.com',
})

---

URL scheme

Required

Why: After Safari or ASWebAuthenticationSession completes, iOS opens your app via a custom URL. Without a matching scheme, the OAuth flow never completes, and the Google Sign-In SDK will crash immediately on button tap.

Use the REVERSED_CLIENT_ID from GoogleService-Info.plist (format: com.googleusercontent.apps.XXXX).

Why can't the SDK fetch this automatically?

URL schemes must be registered statically with the iOS operating system via the Info.plist during app installation so that iOS knows how to route the browser redirect link back into your app. Since iOS does not support dynamic URL scheme registration at runtime, this must be manually configured in your project settings.

Xcode

1. Open your app target → Info → URL Types.
2. Add a URL scheme with the reversed client ID value.

Info.plist example

<key>CFBundleURLTypes</key>
<array>
  <dict>
    <key>CFBundleURLSchemes</key>
    <array>
      <string>com.googleusercontent.apps.YOUR_CLIENT_ID_SUFFIX</string>
    </array>
  </dict>
</array>

Expo

Optional AppDelegate patch on Expo

Why: The config plugin adds the URL scheme from GoogleService-Info.plist or iosUrlScheme. You only need the AppDelegate step if sign-in stalls or you use other URL handlers — see Expo setup.

---

AppDelegate: handle OAuth redirect URLs

After Google Sign-In opens Safari or an in-app browser, iOS returns to your app via the reversed client ID URL scheme. The native SDK must receive that URL through GIDSignIn.sharedInstance.handle(url).

Reference: iOS setup — AppDelegate URL handling (optional on Expo when Google is the sole URL handler; recommended on bare RN).

Situation		Why
Expo — only Google Sign-In, URL scheme from plugin	Optional	Prebuild often registers the scheme; many apps work without editing AppDelegate
Expo — Facebook, deep linking, or other openURL handlers	Required	Chain handlers in generated AppDelegate
Bare RN — interactive sign-in (Safari / account UI)	Recommended	RN 0.77+ templates often ship without application(_:open:options:) — redirects never reach GIDSignIn
Bare RN — multiple openURL handlers	Required	iOS calls one handler; you must chain with ||
Sign-in stuck after browser on any stack	Required	Missing handle(url) is a common cause

Not only for “multiple URL handlers”

Some guides label this step optional when Google is your only URL handler. That assumes your app already implements openURL. Bare React Native 0.77+ often does not — so we recommend adding handle(url) even with a single handler. It becomes required when another SDK also handles URLs, or when sign-in never returns after OAuth.

Rebuild the native app after changing AppDelegate.

Swift (AppDelegate.swift) — React Native 0.77+

Optional on Expo · Recommended on bare RN

Add the method below when you use bare RN, when sign-in stalls after the browser, or when you share openURL with Facebook, React Navigation linking, etc. Skip on Expo if the config plugin URL scheme alone works for you.

import GoogleSignIn

@main
class AppDelegate: UIResponder, UIApplicationDelegate {
  // … existing didFinishLaunchingWithOptions …

  func application(
    _ app: UIApplication,
    open url: URL,
    options: [UIApplication.OpenURLOptionsKey: Any] = [:]
  ) -> Bool {
    // Chain other SDKs first if needed, e.g. Facebook:
    // return FBSDKApplicationDelegate.sharedInstance.application(app, open: url, options: options)
    //   || GIDSignIn.sharedInstance.handle(url)
    return GIDSignIn.sharedInstance.handle(url)
  }
}

See example/ios/NitroGoogleSigninExample/AppDelegate.swift in this repo.

Bridging header

Objective-C projects import #import <GoogleSignIn/GoogleSignIn.h> in the bridging header. Swift apps can import GoogleSignIn directly when the CocoaPod is installed.

Objective-C (AppDelegate.mm)

#import <GoogleSignIn/GoogleSignIn.h>

- (BOOL)application:(UIApplication *)application
            openURL:(nonnull NSURL *)url
            options:(nonnull NSDictionary<NSString *, id> *)options {
  return [GIDSignIn.sharedInstance handleURL:url];
}

---

CocoaPods

Required after installing the npm package

Why: Google Sign-In ships as a native iOS dependency; without installing pods the Xcode project will not link GoogleSignIn.

From your app project root (not inside ios/):

bundle exec pod install --project-directory="ios"

Run bundle install once if your project has a Gemfile. The pod pulls GoogleSignIn (~> 9.x) transitively.

---

iosClientId in configure

Optional

Why optional: The iOS client ID is usually read from GoogleService-Info.plist or inferred when using autoDetect. Set explicitly only if you split config across projects or omit the plist.

GoogleOneTapSignIn.configure({
  webClientId: 'autoDetect',
  iosClientId: 'YOUR_IOS_CLIENT_ID.apps.googleusercontent.com',
})

---

Troubleshooting

Issue	Fix
URL scheme / redirect errors	Verify REVERSED_CLIENT_ID matches Info.plist URL scheme
Sign-in UI never returns / stuck after browser	Add GIDSignIn.sharedInstance.handle(url) in AppDelegate (see above)
autoDetect fails	Add WEB_CLIENT_ID to plist or pass explicit webClientId
Build errors after upgrade	bundle exec pod install --project-directory="ios", clean build folder

See Troubleshooting.