Passkey authentication

Set up and implement passkey authentication using Turnkey’s Kotlin SDK.

Overview

This guide shows how to implement passkey authentication using the Turnkey Kotlin SDK. You’ll add the necessary platform configuration, set up the provider with a proper rpId, and call loginWithPasskey and signUpWithPasskey from your UI.

Passkey Setup

To enable passkeys, you must configure your app’s relying party ID (rpId) correctly. For Android, you must configure a Digital Asset Links by setting up an assetlinks.json file. Refer to our relying party setup guide and Google’s Documentation.

1. Ensure rpId is set correctly in your Turnkey SDK initialization

Set the rpId to the domain you’ve associated (for example, yourdomain.com). This should match the domain configured in Digital Asset Links.

package com.example.test_app

import android.app.Application
import com.turnkey.core.TurnkeyContext
import com.turnkey.models.AuthConfig
import com.turnkey.models.TurnkeyConfig

class App : Application() {
    override fun onCreate() {
        super.onCreate()

        TurnkeyContext.init(
            app = this,
            config = TurnkeyConfig(
                // other config params...
                authConfig = AuthConfig(
                    rpId = "<your-rp-id>",
                )
            )
        )
    }
}

Usage

You can now call loginWithPasskey and signUpWithPasskey from your UI to handle passkey authentication.

Sign up with passkey

import android.os.Bundle
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import com.turnkey.core.TurnkeyContext
import kotlinx.coroutines.launch

class MainActivity : AppCompatActivity() {
    private val activity = this // Reference to the activity for use in passkey flows

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

        val button = findViewById<Button>(R.id.button)
        button.setOnClickListener {
            lifecycleScope.launch {
                try {
                    TurnkeyContext.signUpWithPasskey(activity = activity)
                } catch (t: Throwable) {
                    println(t)
                }
            }
        }
    }
}

Log in with passkey

import android.os.Bundle
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import com.turnkey.core.TurnkeyContext
import kotlinx.coroutines.launch

class MainActivity : AppCompatActivity() {
    private val activity = this // Reference to the activity for use in passkey flows

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

        val button = findViewById<Button>(R.id.button)
        button.setOnClickListener {
            lifecycleScope.launch {
                try {
                    TurnkeyContext.loginWithPasskey(activity = activity)
                } catch (t: Throwable) {
                    println(t)
                }
            }
        }
    }
}

Tips

• Ensure your rpId matches the domain configured in your Digital Asset Links otherwise authentication may fail.
• For local testing, the simplest way to deploy a valid Digital Asset Links file is to set up a simple static file server and use a tunneling service like ngrok and LiveServer to expose it over HTTPS.
• For use in Fragments you use requireActivity() to get the activity reference.

import android.os.Bundle
import android.view.View
import android.widget.Button
import androidx.fragment.app.Fragment
import androidx.lifecycle.lifecycleScope
import com.example.kotlin_demo_wallet.R
import com.turnkey.core.TurnkeyContext
import kotlinx.coroutines.launch

class MyFragment : Fragment(R.layout.fragment_main) {
    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {

        val button = view.findViewById<Button>(R.id.button)
        button.setOnClickListener {
            lifecycleScope.launch {
                try {
                    TurnkeyContext.loginWithPasskey(activity = requireActivity())
                } catch (t: Throwable) {
                    println(t)
                }
            }
        }
    }
}