Firebase Email Verification Kotlin

** Note Some Image text is blank for security purposes

Output:

     Login or register with a valid email address.

Click on the Verify Email Button. A link will sent to your mailbox with the name noreply

After getting the mail click on the link you will be verified. Now restart your app. you will able to see your mail is verified.

Now Let's start the project.

1/ Create an Empty Views Activity project: Firebase Email Verification

2/ Create another 2 activities one by one LoginActivity & RegisterActivity

3/ Modify your AnroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.MyApplication"
        tools:targetApi="31">
        <activity
            android:name=".RegisterActivity"
            android:exported="true"/>

        <activity
            android:name=".LoginActivity"
            android:exported="true" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".MainActivity"
            android:exported="true">
        </activity>
    </application>

</manifest>

4/ We will work with recently created activities after connecting the Firebase with the app.

5/ Go to Tools > Firebase

after clicking the firebase shown in the picture above the Firebase assistance tool window will open. then click on Authentication

after clicking on the Authentication, a new window will open click on authentication using Google [Java ]

then another new window will open. Click on Connect to Firebase

after clicking on Connect to Firebase you will redirect to your web browser. you must log in with your Gmail in the browser.

6/ Now create, connect, and authentication permission in the Firebase project

   6.1/ Click on the Create New project. after click a new window will open

  6.2/ Firebase automatically suggests you a name. then click on Continue

  6.3/ click on Continue

   6.4/ Select Default account for Firebase and click on Create Project. You project will start making.

  6.5/After completing the project, you will see the button Continue click on it

  6.6/ Then you will redirect to your project. and you will able to see a popup window here. click on Connect

6.7/ Close the project and again open your project from the console.

6.8/ On the sidebar from Build you can find the option Authentication. Click on it

6.7/After clicking on Authentication the new window for authentication will open. Click on Get Started

6.8/ Select Email/Password Provider from the new window. if not visible then click on the sign-in option and then click on Add Provider.

6.9/ Enable Email/Password Provider and Save it.

Here working with Firebase Project is Complete.

Now Go to your Android Studio You can see Firebase connected on the Firebase tool window where you left the last time

7/ Click on Add the Firebase Authentication SDK to your App. The new popup window will open

8/ Click on Accept Change. SDK will automatically add to your project.

Firebase Connection and SDK setup are complete. Now we will work with those activities.

9/ Modify your activity_login.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_margin="16dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".LoginActivity">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        >
        <LinearLayout
            android:id="@+id/linearlayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent">

            <EditText
                android:id="@+id/email"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="Enter Your Email here" />

            <EditText
                android:id="@+id/password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:hint="Enter Your password here" />
        </LinearLayout>

        <Button
            app:layout_constraintTop_toBottomOf="@+id/linearlayout"
            android:layout_marginTop="16dp"
            android:id="@+id/loginButton"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Login"
            />
        <TextView
            android:id="@+id/or"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            app:layout_constraintTop_toBottomOf="@+id/loginButton"
            app:layout_constraintStart_toStartOf="@id/loginButton"
            app:layout_constraintEnd_toEndOf="@id/loginButton"
            android:layout_marginTop="16dp"
            android:text="OR"
            android:textSize="22sp"
            />
        <TextView
            android:id="@+id/registerButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            app:layout_constraintTop_toBottomOf="@+id/or"
            app:layout_constraintStart_toStartOf="@id/or"
            app:layout_constraintEnd_toEndOf="@id/or"
            android:layout_marginTop="16dp"
            android:text="Create an account"
            android:textSize="22sp"
            android:textColor="#21608B"
            />
    </androidx.constraintlayout.widget.ConstraintLayout>


</androidx.constraintlayout.widget.ConstraintLayout>

10/ Modify your LoginActivity.kt:

package com.zissofworks.myapplication

import android.content.Intent
import android.os.Bundle
import android.widget.Button
import android.widget.EditText
import android.widget.TextView
import android.widget.Toast
import androidx.activity.enableEdgeToEdge
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.ViewCompat
import androidx.core.view.WindowInsetsCompat
import com.google.firebase.auth.FirebaseAuth


class LoginActivity : AppCompatActivity() {

    private lateinit var email: EditText
    private lateinit var password:EditText
    private lateinit var loginButton: Button
    private lateinit var registerButton: TextView
    private lateinit var auth: FirebaseAuth

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContentView(R.layout.activity_login)
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main)) { v, insets ->
            val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
            insets
        }

        email = findViewById(R.id.email)
        password = findViewById(R.id.password)
        loginButton = findViewById(R.id.loginButton)
        registerButton = findViewById(R.id.registerButton)
        auth = FirebaseAuth.getInstance()

        loginButton.setOnClickListener{
            val emailTxt = email.text.toString()
            val passwordTxt = password.text.toString()
            loginUser(emailTxt, passwordTxt)
        }

        registerButton.setOnClickListener { startActivity(Intent(this@LoginActivity, RegisterActivity::class.java))}
    }
    private fun loginUser(email:String, password: String) {
        auth.signInWithEmailAndPassword(email, password)
            .addOnCompleteListener {
                if (it.isSuccessful) {
                    startActivity(Intent(this@LoginActivity, MainActivity::class.java))
                    finish();
                } else {
                    Toast.makeText(this@LoginActivity, "Login failed.", Toast.LENGTH_SHORT).show()
                }
            }
    }

    @Override
    override fun onStart() {
        super.onStart()
        if(auth.currentUser != null){
            startActivity(Intent(this@LoginActivity, MainActivity::class.java))
            finish()
        }
    }
}

11/ Modify your activity_register.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_margin="16dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".RegisterActivity">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        >
        <LinearLayout
            android:id="@+id/linearlayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent">

            <EditText
                android:id="@+id/email"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="Enter Your Email here" />

            <EditText
                android:id="@+id/password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:hint="Enter Your password here" />
        </LinearLayout>

        <Button
            app:layout_constraintTop_toBottomOf="@+id/linearlayout"
            android:layout_marginTop="16dp"
            android:id="@+id/registerButton"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Register"
            />
        <TextView
            android:id="@+id/or"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            app:layout_constraintTop_toBottomOf="@+id/registerButton"
            app:layout_constraintStart_toStartOf="@id/registerButton"
            app:layout_constraintEnd_toEndOf="@id/registerButton"
            android:layout_marginTop="16dp"
            android:text="OR"
            android:textSize="22sp"
            />
        <TextView
            android:id="@+id/loginButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            app:layout_constraintTop_toBottomOf="@+id/or"
            app:layout_constraintStart_toStartOf="@id/or"
            app:layout_constraintEnd_toEndOf="@id/or"
            android:layout_marginTop="16dp"
            android:text="Login existing account"
            android:textSize="22sp"
            android:textColor="#21608B"
            />
    </androidx.constraintlayout.widget.ConstraintLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

12/ Modify your RegisterActivity.kt:

package com.zissofworks.myapplication

import android.content.Intent
import android.os.Bundle
import android.widget.Button
import android.widget.EditText
import android.widget.TextView
import android.widget.Toast
import androidx.activity.enableEdgeToEdge
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.ViewCompat
import androidx.core.view.WindowInsetsCompat
import com.google.firebase.auth.FirebaseAuth


class RegisterActivity : AppCompatActivity() {
    private lateinit var email: EditText
    private lateinit var password:EditText
    private lateinit var registerButton: Button
    private lateinit var loginButton: TextView
    private lateinit var mAuth: FirebaseAuth

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContentView(R.layout.activity_register)
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main)) { v, insets ->
            val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
            insets
        }

        email = findViewById(R.id.email)
        password = findViewById(R.id.password)
        registerButton = findViewById(R.id.registerButton)
        loginButton = findViewById(R.id.loginButton)

        mAuth = FirebaseAuth.getInstance();

        registerButton.setOnClickListener {
            val emailTxt = email.text.toString()
            val passwordTxt = password.text.toString()
            registerUser(emailTxt, passwordTxt)
        }

        loginButton.setOnClickListener { startActivity(Intent(this@RegisterActivity, RegisterActivity::class.java)) }
    }

    private fun registerUser(email: String, password: String){
        mAuth.createUserWithEmailAndPassword(email, password).addOnCompleteListener{
            if (it.isSuccessful) {
                val intent = Intent(this@RegisterActivity, MainActivity::class.java)
                intent.putExtra("email", FirebaseAuth.getInstance().currentUser?.email)
                startActivity(intent)
                finish()
            } else {
                Toast.makeText(this@RegisterActivity, "Registration failed.", Toast.LENGTH_SHORT).show()
            }
        }
    }
}

13/ Modify your activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:gravity="center"
    android:orientation="vertical"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/emailTxt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:textSize="22sp"/>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_gravity="center"
        android:layout_marginTop="8dp"
        >
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="is verified Email ? "
            />
        <TextView
            android:id="@+id/verifiedOrNot"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Verified "
            android:textStyle="bold"
            />
    </LinearLayout>

    <Button
        android:id="@+id/verifyBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Verify Email"
        android:layout_marginTop="16dp"
        android:visibility="gone"
        />

    <Button
        android:id="@+id/logOut"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Logout"/>

</LinearLayout>

14/ Modify your MainActivity.kt:

package com.zissofworks.myapplication

import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.TextView
import android.widget.Toast
import androidx.activity.enableEdgeToEdge
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.ViewCompat
import androidx.core.view.WindowInsetsCompat
import com.google.firebase.auth.FirebaseAuth


class MainActivity : AppCompatActivity() {
    private lateinit var emailTxt: TextView
    private lateinit var  verifiedOrNot:TextView
    private lateinit var  verifyBtn: Button
    private lateinit var  logOut:Button
    private lateinit var  auth: FirebaseAuth


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContentView(R.layout.activity_main)
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main)) { v, insets ->
            val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
            insets
        }

        auth = FirebaseAuth.getInstance()

        emailTxt = findViewById(R.id.emailTxt)
        verifiedOrNot = findViewById(R.id.verifiedOrNot)
        verifyBtn = findViewById(R.id.verifyBtn)
        logOut = findViewById(R.id.logOut)


        emailTxt.text = auth.currentUser?.email


        if (auth.currentUser?.isEmailVerified == true) {
            verifiedOrNot.text = "Verified"
            verifyBtn.visibility = View.GONE

        } else {
            verifiedOrNot.text = "Not Verified"
            verifyBtn.visibility = View.VISIBLE
        }

        logOut.setOnClickListener{
            auth.signOut();
            finish();
        }

        verifyBtn.setOnClickListener{
            auth.currentUser?.sendEmailVerification()?.addOnCompleteListener{
                if (it.isSuccessful) {
                    Toast.makeText(this@MainActivity, "Verification email sent!", Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(this@MainActivity, "Failed to send verification email.", Toast.LENGTH_SHORT).show();
                }
            }
        }
    }

    override fun onStart() {
        super.onStart()
        auth.currentUser!!.reload().addOnCompleteListener {
            if (auth.currentUser!!.isEmailVerified) {
                verifiedOrNot.text = "Verified"
                verifyBtn.visibility = View.GONE
            } else {
                verifiedOrNot.text = "Not Verified"
                verifyBtn.visibility = View.VISIBLE
            }
        }
    }
}

Now run your app and test with a valid email address.