Email and SMS OTP authentication

Set up and implement email OTP authentication using @turnkey/react-native-wallet-kit with Expo Router.

Overview

This guide shows how to implement email OTP authentication using @turnkey/react-native-wallet-kit in an Expo app. We’ll trigger an OTP to a user’s email address, navigate to a verification screen, and verify the 6-digit code.

Before you begin:

• Ensure you’ve completed the provider setup from Getting Started and enabled the Auth Proxy with Email OTP in the Turnkey Dashboard.
• In your TurnkeyProvider config, make sure auth.otp.email is enabled (or enabled via dashboard). See Getting Started for the full provider example.

Request an OTP (email)

Create or update your login screen to request an email OTP using initOtp. The snippet below uses Expo Router to navigate to an otp screen with the returned otpId and the email address.

app/index.tsx

import { useState } from "react";
import { Alert, Button, TextInput, View } from "react-native";
import { useRouter } from "expo-router";
import { useTurnkey } from "@turnkey/react-native-wallet-kit";
import { OtpType } from "@turnkey/core";

export default function LoginScreen() {
  const router = useRouter();
  const { initOtp } = useTurnkey();
  const [email, setEmail] = useState("");

  const handleEmailSubmit = async () => {
    if (!email || !email.includes("@")) {
      Alert.alert("Invalid Email", "Please enter a valid email address");
      return;
    }

    const otpId = await initOtp({
      otpType: OtpType.Email,
      contact: email,
    });

    if (!otpId) {
      Alert.alert("Error", "Failed to initialize OTP");
      return;
    }

    router.push({ pathname: "/otp", params: { email, otpId } });
  };

  return (
    <View style={{ padding: 24 }}>
      <TextInput
        value={email}
        onChangeText={setEmail}
        placeholder="[e-mail]"
        autoCapitalize="none"
        keyboardType="email-address"
        style={{ borderWidth: 1, padding: 12, marginBottom: 12 }}
      />
      <Button title="Continue with email" onPress={handleEmailSubmit} />
    </View>
  );
}

Verify the OTP code

On a separate otp screen, read the email and otpId from the route and call completeOtp with the user-entered 6-digit code.

app/otp.tsx

import { useState } from "react";
import { Alert, Button, TextInput, View } from "react-native";
import { useLocalSearchParams, useRouter } from "expo-router";
import { useTurnkey } from "@turnkey/react-native-wallet-kit";
import { OtpType } from "@/types/types"; // or import { OtpType } from "@turnkey/core"

export default function OtpScreen() {
  const router = useRouter();
  const { completeOtp } = useTurnkey();
  const { email, otpId } = useLocalSearchParams<{
    email: string;
    otpId: string;
  }>();
  const [otpCode, setOtpCode] = useState("");

  const handleVerify = async () => {
    if (!otpId) {
      Alert.alert(
        "Missing OTP",
        "We could not find your OTP session. Please try again."
      );
      return;
    }
    // Note: The default OTP length is 6 but can be up to 9 digits
    // Adjust this conditional guard accordingly
    if (otpCode.length !== 6) {
      Alert.alert("Invalid Code", "Please enter a 6-digit code");
      return;
    }

    await completeOtp({
      otpId,
      otpCode,
      contact: String(email),
      otpType: OtpType.Email,
    });

    // Navigate to the main app once the OTP is verified successfully
    router.replace("/(main)");
  };

  return (
    <View style={{ padding: 24 }}>
      <TextInput
        value={otpCode}
        onChangeText={setOtpCode}
        placeholder="Enter 6-digit code"
        keyboardType="number-pad"
        maxLength={6}
        style={{
          borderWidth: 1,
          padding: 12,
          marginBottom: 12,
          letterSpacing: 4,
        }}
      />
      <Button title="Verify" onPress={handleVerify} />
    </View>
  );
}

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.