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Overview

This guide shows how to implement email OTP authentication using the Turnkey Kotlin SDK. We’ll trigger an OTP to a user’s email address and verify the 6-digit code. Before you being:
  • Ensure you’ve completed the provider setup from Getting Started and enabled the Auth Proxy with Email OTP in the Turnkey Dashboard.
  • In your Turnkey SDK initialization, make sure authConfig.methods.emailOtpAuthEnabled is set to true (or enabled via dashboard). See Getting Started for the full provider example.

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Request an OTP (email)

Create or update your login screen to request an email OTP using initOtp. The snippet below demonstrates how to trigger the OTP and verify the 6-digit code to log in.
For a full flow example, see the Kotlin SDK Example App 
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import com.turnkey.core.TurnkeyContext
import com.turnkey.models.OtpType
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.asStateFlow
import kotlinx.coroutines.flow.firstOrNull
import kotlinx.coroutines.launch

class MainActivity : AppCompatActivity() {
    private val _otpId = MutableStateFlow<String?>(null)
    val otpId: StateFlow<String?> = _otpId.asStateFlow()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContentView(R.layout.activity_main)

        val button = findViewById<Button>(R.id.button)

        button.setOnClickListener {
            lifecycleScope.launch {
                try {
                    val email = "user@example.com"
                    val ( otpId ) = TurnkeyContext.initOtp(
                        otpType = OtpType.OTP_TYPE_EMAIL,
                        contact = email
                    )

                    println("OTP sent to email: $email")

                    // Store otpId for verification step
                    _otpId.value = otpId
                } catch (e: Exception) {
                    println("Error sending OTP: ${e.message}")
                }
            }
        }
    }
}

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Verify the OTP code

To verify the OTP code entered by the user, use the loginOrSignUpWithOtp function with the otpId, otpCode, and contact email. This will automatically log in or sign up the user based on whether they already own an existing sub-org. 
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import com.turnkey.core.TurnkeyContext
import com.turnkey.models.OtpType
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.asStateFlow
import kotlinx.coroutines.flow.firstOrNull
import kotlinx.coroutines.launch

class MainActivity : AppCompatActivity() {
    private val _otpId = MutableStateFlow<String?>(null)
    val otpId: StateFlow<String?> = _otpId.asStateFlow()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContentView(R.layout.activity_main)

        val button = findViewById<Button>(R.id.button)

        button.setOnClickListener {
            lifecycleScope.launch {
                try {
                    val email = "user@example.com"
                    val code = "abc123" // Get this from user input

                    val otpId = otpId.value ?: throw IllegalStateException("OTP ID is null")

                    TurnkeyContext.loginOrSignUpWithOtp(
                        otpId = otpId,
                        otpCode = code,
                        contact = email,
                        otpType = OtpType.OTP_TYPE_EMAIL
                    )

                    println("OTP verified successfully")
                } catch (e: Exception) {
                    println("Error verifying OTP: ${e.message}")
                }
            }
        }
    }
}

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Notes

  • Default OTP length is 6; if you’ve customized OTP in the dashboard, validate accordingly.
  • If you need to resend a code, you can call initOtp again with the same email.