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

Activate Firestore Database

Note

You can skip this step if you already activated Firestore Database.

To use KMPShip's authentication features, you need to activate the Firestore Database in your Firebase project.

If you haven't done this yet, follow this step-by-step guide:

👉 Activate Firestore Database

---

Supported providers

KMPShip supports the following authentication providers out of the box:

• Google Sign In
• Apple Sign In
• Email & Password

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 Sign in with Apple in your iOS app using Firebase Authentication, follow these steps carefully:

Step 1: Create a Service ID in Apple Developer Portal

1. Visit Service IDs and click the "+" button.
2. Ensure Service IDs is selected, then click Continue.

3. Fill out the form:

   • Description: MyProject Apple Sign In (replace MyProject with your actual project name)
   • Identifier: com.example.myapp.apple.signin (replace com.example.myapp with your app's package name)

   • Click Continue, then on the next screen:

   • Enable Sign In with Apple

   • Click Configure
   • In Primary App ID, select your app’s registered App ID (the one tied to your bundle ID)
   • Click Save
   • Under Domains and Subdomains, add your website domain (e.g., kmpship.app)
   • Under Return URLs, enter:

   https://YOUR_FIREBASE_PROJECT_ID.firebaseapp.com/__/auth/handler
   

   (Replace YOUR_FIREBASE_PROJECT_ID with your actual Firebase project ID)

   • Click Next, then Done
   • Finally, click Continue, then Save

Step 2: Create a Private Key for Apple Sign-In

1. Visit Keys and click the "+" button.
2. Enter a name for your key (e.g., MyProject Apple Auth Key)
3. Enable Sign in with Apple and click Configure.
4. In the Primary App ID dropdown, select the same App ID you chose earlier.
5. Click Save, then Continue.
6. Click Register, then Download the .p8 private key.
7. Save this file securely — you won't be able to download it again.

Step 3: Enable and configure Apple provider in Firebase

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

3. Fill out the following fields using the values from previous steps:

   • Services ID: the Service ID you created in Step 1
   • Apple Team ID: your Apple Team ID (found at Apple Developer > Account → Membership Details)
   • Key ID: the ID from your newly created key in Step 2
   • Private key: paste the content of the downloaded .p8 file
   • Click Save

Step 4: Enable Sign in with Apple in Xcode

1. Open your project in Xcode.
2. Select your app target > Signing & Capabilities.
3. Click “+ Capability”, then add Sign In with Apple.
4. Ensure the bundle identifier matches the one used in your Apple Developer configuration.

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.