Skip to content

Authentication

KMPShip includes built-in support for Firebase Authentication using Passage, allowing you to easily implement user authentication in your app.

Prerequisite: Create a Firebase Project

Note

You can skip this step if you already have a Firebase project set up.

Before configuring authentication, you must have a Firebase project already set up.

If you haven't done this yet, follow the linked guide and connect both your Android and iOS apps before continuing:

👉 Create a Firebase Project

Supported providers

KMPShip supports the following authentication providers out of the box:

None of these providers are mandatory — you can enable only the ones you need.

Google Sign In

  1. In the Firebase Console, go to Authentication > Sign-in method
  2. Enable Google as a provider.
  3. Copy the Web client ID provided by Firebase.

Android setup

Store the Web client ID in your local.properties file like this:

GOOGLE_SIGN_IN_WEB_CLIENT_ID={Web client ID provided by Firebase}

This value will be injected automatically into your Android build.

iOS setup

  1. Open the GoogleService-Info.plist file downloaded from Firebase.

  2. Copy the values of the following keys:

    • CLIENT_ID
    • REVERSED_CLIENT_ID

  3. Open your app’s Info.plist file and add the following keys:

<key>GIDClientID</key>
<string>YOUR_GOOGLE_SIGN_IN_WEB_CLIENT_ID</string>

<key>CFBundleURLTypes</key>
<array>
  <dict>
    <key>CFBundleURLSchemes</key>
    <array>
      <string>YOUR_REVERSED_GOOGLE_SIGN_IN_WEB_CLIENT_ID</string>
    </array>
  </dict>
</array>

Replace:

  • YOUR_GOOGLE_SIGN_IN_WEB_CLIENT_ID with the CLIENT_ID value
  • YOUR_REVERSED_GOOGLE_SIGN_IN_WEB_CLIENT_ID with the REVERSED_CLIENT_ID value

Apple Sign-In (iOS only)

To support Apple Sign-In in your app, you must:

  1. In the Firebase Console, go to Authentication > Sign-in method
  2. Enable Apple as a provider.

  3. Configure Apple Sign-In for iOS:

    1. Go to the Apple Developer Portal and:

      • Create a Services ID
      • Create a Key with Sign in with Apple enabled
      • Link both to your app’s bundle identifier

    2. In Firebase:

      • Add your Services ID
      • Upload the Key ID and Private Key

      • Set your Team ID (found in the Apple Developer Account settings)

      • In Xcode:

        • Make sure the Sign In with Apple capability is enabled in your app’s target under Signing & Capabilities
        • Confirm the app’s bundle identifier matches the one registered in the Apple Developer Portal

Email & Password

  1. In the Firebase Console, go to Authentication > Sign-in method
  2. Enable Email/Password as a provider.

Once enabled, KMPShip provides:

  • A built-in Sign up and Sign in form for email/password users.
  • Support for password reset: users can receive a password recovery email and reset their password directly in the app.
  • Support for email verification: users can verify their email address after signing up.
  • Firebase error handling for common issues (e.g., invalid credentials, user not found).

Authentication setup complete

You have successfully configured authentication in your KMPShip app. Users can now sign in using Google, Apple, or email/password methods.