Using Firebase with Web3Auth PnP Android SDK

This guide will cover the basics of how to use the Web3Auth Android SDK in your Android application with Firebase.

Demo APK: Download

Repository: https://github.com/Web3Auth/web3auth-pnp-examples/tree/main/android/android-firebase-example

Live Demo

Quick Start​

npx degit Web3Auth/web3auth-pnp-examples/android/android-firebase-example w3a-android-firebase-demo
# Open in Android Studio

How it works?​

When integrating Web3Auth Android SDK with Social Login the flow looks something like this:

• When a user logs in with Firebase, Firebase sends a JWT id_token to the app. This JWT token is sent to the Web3Auth SDK's login function.

• Finally, on successful validation of the JWT token, Web3Auth SDK will generate a private key for the user, in a self-custodial way, resulting in easy onboarding for your user to the application.

Prerequisites​

• For Web Apps: A basic knowledge of JavaScript is required to use Web3Auth SDK.

• For Mobile Apps: For the Web3Auth Mobile SDKs, you have a choice between iOS, Android, React Native & Flutter. Please refer to the Web3Auth SDK Reference for more information.

• Create a Web3Auth account on the Web3Auth Dashboard

• Android API version 21 or newer.

• A Firebase account to be used as Federated Identity Provider.

• A Google Developer account to be used as Identity provider for Firebase.

Setup​

Setup your Firebase Project​

• Go to your Firebase console and create a Web App. Follow this guide on how to setup your Firebase Web App project.

Create a Firebase Project​

• Create a new project by clicking on Add project or use your existing project from Firebase console.

  

• Give your project a name and click on Continue

  

• Finally, click on Create Project

  

Select Authentication Provider​

• Once the project is created. Set up authentication by clicking on the Authentication card from the home screen of your project or choose Authentication under Build from the left sidebar.

  

• From Sign-in method tab, select any provider you wish to enanle. For the purpose of this guide, we'll be enabling Google.

  

• Finally, toggle the enable button and click on Save

  

Configure Firebase for Android​

• Once the project is created and authentication is configured. Let's use Firebase for Android by clicking on the Android button on the home screen of your project.

  

• In the next screen, enter the Android package name and click on Register app button to register the app for Android.

  

• In the Next screen, Download and add config file to your Android Studio Project as shown below. Then Click on Next button.

  

• Next screen shows ways to add Firebase to your application. To make the google-services.json config values accessible to Firebase SDKs, you need the Google services Gradle plugin. We will be adding the buildscript dependency to the <project>/build.gradle file.

  

• Then, in your module (app-level) build.gradle file, add both the google-services plugin and any Firebase SDKs that you want to use in your app:

  

• After adding the plugin and the desired SDKs, sync your Android project with Gradle files.

  

Setup your Web3Auth Dashboard​

• Create a Project from the Project Section of the Web3Auth Developer Dashboard.

  

  • Enter your desired Project name.

  • Select the Product you want to use. For this guide, we'll be using the Plug n Play product.

  • Select the Platform type you want to use. For this guide, we'll be using the Android as the platform.

  • Select the Web3Auth Network as Sapphire Devnet. We recommend creating a project in the Sapphire Devnet network during development. While moving to a production environment, make sure to convert your project to Sapphire Mainnet or any of the legacy mainnet network Mainet, Aqua, or Cyan network. Otherwise, you'll end up losing users and keys.

  • Select the blockchain(s) you'll be building this project on. For interoperability with Torus Wallets, you have the option of allowing the user's private key to be used in other applications using Torus Wallets (EVM, Solana, XRPL & Casper).

  • Finally, once you create the project, you have the option to whitelist your URLs for the project. Please whitelist the domains where your project will be hosted.

    

• Add {YOUR_APP_PACKAGE_NAME}://auth in the Whitelist URL field of the Web3Auth Dashboard.

Create Firebase Verifier on Web3Auth Dashboard​

• Create a Verifier from the Custom Auth Section of the Web3Auth Developer Dashboard with following configuration:

  • Choose a name of your choice for the verifier identifier. eg. w3a-firebase-verifier
  • Select environment: testnet, mainnet,aqua, or cyan as per your requirement.
  • Select Custom from the Login Provider.
  • Select Sub for the JWT Verifier ID.
  • Enter https://www.googleapis.com/service_accounts/v1/jwk/securetoken@system.gserviceaccount.com as the JWK endpoint for Firebase's idToken.
  • JWT validation fields:
    • iss: https://securetoken.google.com/<firebase-project-id>.
    • aud: <firebase-project-id>
  • Click on Create button to create your verifier. It may take up to 10 minutes to deploy verifier on testnet. You'll receive an email once it's complete.

  

• You will require the verifierName of the newly created verifier and clientId of the Plug and Play Project.

Using the Web3Auth SDK​

To use the Web3Auth SDK, you'll need to add the dependency of the respective platform SDK of Web3Auth to your project. To know more about the available SDKs, please have a look at our SDK page.

For this guide, we will be using the Web3Auth Android SDK.

Add Web3Auth to Gradle​

In your project-level gradle file add JitPack repository:

dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        google()
        mavenCentral()
        maven { url "https://jitpack.io" } // <-- Add this line
    }
}

Then, in your app-level build.gradle dependencies section, add the following:

dependencies {
    // ...
    implementation 'com.github.web3auth:web3auth-android-sdk:7.1.1'
}

Permissions​

Open your app's AndroidManifest.xml file and add the following permission:

<uses-permission android:name="android.permission.INTERNET" />

Note: The <uses-permission> element must be a direct child of the <manifest> root element.

Configuration​

Configure a Plug n Play project​

• Go to Developer Dashboard, create or select a Web3Auth project.
• Add {SCHEME}://{YOUR_APP_PACKAGE_NAME} to Whitelist URLs. eg. w3a://com.example.w3aflutter
• Copy the Client ID from Project Details for initilization usage later.

Configure Deep Link​

Open your app's AndroidManifest.xml file and add the following deep link intent filter to your Main activity

<intent-filter>
  <action android:name="android.intent.action.VIEW" />

  <category android:name="android.intent.category.DEFAULT" />
  <category android:name="android.intent.category.BROWSABLE" />

  <data android:scheme="{scheme}" android:host="{YOUR_APP_PACKAGE_NAME}" android:path="/auth" />
  <!-- Accept URIs: w3a://com.example.w3aflutter -->
</intent-filter>

Make sure your Main activity launchMode is set to singleTop in your AndroidManifest.xml

<activity
  android:launchMode="singleTop"
  android:name=".YourActivity">
  // ...
</activity>

Initialization​

Initialization is a two-step process:

1. Creating a Web3Auth Instance
2. Setting a Result URL

Please note that these are the most critical steps where you must pass on different parameters according to the preference of your project. Additionally, You must configure Whitelabeling and Custom Authentication within this step if you wish to customize your Web3Auth Instance.

Create Web3Auth Instance​

In your activity, create a Web3Auth instance with your Web3Auth project's configurations.

web3Auth = Web3Auth(
  Web3AuthOptions(
    context = this,
    clientId = getString(R.string.web3auth_project_id), // pass over your Web3Auth Client ID from Developer Dashboard
    network = Network.MAINNET, // pass over the network you want to use (MAINNET, TESTNET, CYAN, AQUA )
    redirectUrl = Uri.parse("{YOUR_APP_PACKAGE_NAME}://auth"), // your app's redirect URL
    loginConfig = hashMapOf("jwt" to LoginConfigItem(
        verifier = "web3auth-firebase-examples",
        typeOfLogin = TypeOfLogin.JWT,
        name = "Firebase Login",
        clientId = getString(R.string.web3auth_project_id)
        )
    )
  )
)

// Handle user signing in when app is not alive
web3Auth.setResultUrl(intent?.data)

Add the below line to your app/res/values/strings.xml file and paste your Web3Auth Client ID:

<resources>
    <!-- ... -->
    <string name="web3auth_project_id">CLIENT_ID_FROM_WEB3AUTH_DASHBOARD</string>
    <!-- ... -->
</resources>

Read more about initializing the Android SDK here.

Set Result URL​

Whenever user initiates a login flow, a new intent of CustomTabs is launched. It’s necessary step to use setResultUrl in onNewIntent to successful track the login process.

override fun onNewIntent(intent: Intent?) {
  super.onNewIntent(intent)

  // Handle user signing in when app is active
  web3Auth.setResultUrl(intent?.data)
}

Authentication​

Logging in​

Once initialized, you can use the web3Auth.login(LoginParams("{selectedLoginProvider}")) function to authenticate the user when they click the login button.

private fun signIn() {
  // Initialize Firebase Auth
  auth = Firebase.auth
  auth.signInWithEmailAndPassword("android@firebase.com", "Android@Web3Auth")
    .addOnCompleteListener(this) { task ->
        if (task.isSuccessful) {
            // Sign in success, update UI with the signed-in user's information
            Log.d(TAG, "signInWithEmail:success")
            val user = auth.currentUser
            user!!.getIdToken(true).addOnSuccessListener { result ->
                val idToken = result.token

                Log.d(TAG, "GetTokenResult result = $idToken")
                val selectedLoginProvider = Provider.JWT
                val loginCompletableFuture: CompletableFuture<Web3AuthResponse> = web3Auth.login(LoginParams(selectedLoginProvider, extraLoginOptions = ExtraLoginOptions(domain = "firebase", id_token = idToken)))

                loginCompletableFuture.whenComplete { loginResponse, error ->
                    if (error == null) {
                        println(loginResponse)
                        reRender(loginResponse)
                    } else {
                        Log.d("MainActivity_Web3Auth", error.message ?: "Something went wrong" )
                    }
                }
            }
        } else {
            // If sign in fails, display a message to the user.
            Log.w(TAG, "signInWithEmail:failure", task.exception)
            Toast.makeText(baseContext, "Authentication failed.",
                Toast.LENGTH_SHORT).show()

        }
    }
}

When connecting, the login function takes the LoginParams arguments for the login. See the LoginParams for more details.

Sample loginResponse​

{
  "privKey": "0ajjsdsd....",
  "userInfo": {
    "email": "w3a-heroes@web3auth.com",
    "name": "Web3Auth Heroes",
    "profileImage": "https://lh3.googleusercontent.com/a/Ajjjsdsmdjmnm...",
    "verifier": "torus",
    "verifierId": "w3a-heroes@web3auth.com",
    "typeOfLogin": "google",
    "aggregateVerifier": "w3a-google-sapphire",
    "dappShare": "", // 24 words of seed phrase will be sent only incase of custom verifiers
    "idToken": "<jwtToken issued by Web3Auth>",
    "oAuthIdToken": "<jwtToken issued by OAuth Provider>", // will be sent only incase of custom verifiers
    "oAuthAccessToken": "<accessToken issued by OAuth Provider>", // will be sent only incase of custom verifiers
    "isMfaEnabled": false // Returns whether the user has enabled MFA or not
  },
  "ed25519PrivKey": "666523652352635....",
  "coreKitKey": "0xajjsdsd....",
  "coreKitEd25519PrivKey": "666523652352635....",
  "sessionId": "0xajjsdsd...."
}

Get the User Profile​

// Assuming the user is logged in, get the user profile from the web3AuthResponse
val userInfo = web3AuthResponse.userInfo

Using the web3Auth.login function, you can get the details of the logged in user. Please note that these details are not stored anywhere in Web3Auth network.

If you wish you add Multi Factor Authentication, use dApp Share or select Curve for your Android application, read the linked documentation.

• Multi Factor Authentication
• Using dApp Share
• Selecting Curve

Logout​

Logging out your user is as simple as calling the logout() function. This method will clear the session data and the user will be logged out from Web3Auth.

private fun logOut() {
  val logoutCompletableFuture =  web3Auth.logout()
  logoutCompletableFuture.whenComplete { _, error ->
  if (error == null) {
    // render logout UI
  } else {
    // render error UI
  }
  }
}

Interacting with the Blockchain​

Get Account​

// checkout the Connect Blockchain > Ethereum > Android to get full code.
private fun getAddress(): String {
  println("Address:, ${credentials.address}")
  return credentials.address
}

// Setup UI and event handlers
val getBalanceButton = findViewById<Button>(R.id.getBalanceButton)
getBalanceButton.setOnClickListener { getAddress() }

Get Balance​

// checkout the Connect Blockchain > Ethereum > Android to get full code.
private fun getBalance(): BigInteger? {
  val publicAddress = credentials.address
  val ethBalance: EthGetBalance = web3.ethGetBalance(publicAddress, DefaultBlockParameterName.LATEST).sendAsync().get()
  println("Balance: ${ethBalance.balance}")
  return ethBalance.balance
}

// Setup UI and event handlers
val getBalanceButton = findViewById<Button>(R.id.getBalanceButton)
getBalanceButton.setOnClickListener { getBalance() }

Send Transaction​

// checkout the Connect Blockchain > Ethereum > Android to get full code.
private fun sendTransaction(amount: Double, recipientAddress: String): String? {
  val ethGetTransactionCount: EthGetTransactionCount = web3.ethGetTransactionCount(credentials.address, DefaultBlockParameterName.LATEST).sendAsync().get()
  val nonce: BigInteger = ethGetTransactionCount.transactionCount
  val value: BigInteger = Convert.toWei(amount.toString(), Convert.Unit.ETHER).toBigInteger()
  val gasLimit: BigInteger = BigInteger.valueOf(21000)
  val chainId: EthChainId = web3.ethChainId().sendAsync().get()

  // Raw Transaction
  val rawTransaction: RawTransaction = RawTransaction.createTransaction(
    chainId.chainId.toLong(),
    nonce,
    gasLimit,
    recipientAddress,
    value,
    "",
    BigInteger.valueOf(5000000000),
    BigInteger.valueOf(6000000000000)
  )

  val signedMessage: ByteArray = TransactionEncoder.signMessage(rawTransaction, credentials)
  val hexValue: String = Numeric.toHexString(signedMessage)
  val ethSendTransaction: EthSendTransaction = web3.ethSendRawTransaction(hexValue).sendAsync().get()
  return if(ethSendTransaction.error != null) {
    println("Tx Error: ${ethSendTransaction.error.message}")
    ethSendTransaction.error.message
  } else {
    println("Tx Hash: ${ethSendTransaction.transactionHash}")
    ethSendTransaction.transactionHash
  }
}

// Setup UI and event handlers
val sendTransactionButton = findViewById<Button>(R.id.sendTransactionButton)
sendTransactionButton.setOnClickListener { sendTransaction() }

Example code​

The code for the application we developed in this guide can be found in the Web3Auth Android Firebase Example. Check it out and try running it locally yourself!

Also, checkout other examples:

• Using Web3Auth Android SDK
• Using Auth0 with Android SDK
• Using Aggregate Verifier with Android SDK

Questions?​

Ask us on Web3Auth's Community Support Portal