Cotter
  • 🚀Getting Started
  • Features & Concepts
    • 💬Sign In with Email/Phone Number
    • 🔐Sign In with Device
      • How it works
    • 🧬Sign In with WebAuthn
  • 📌Quickstart Guides
    • All Guides & Tutorials
    • HTML – Sign in with Email/Phone
    • React – Sign in with Email/Phone
    • React – WebAuthn
    • ▲ Next.js
    • Angular
    • Webflow
    • Bubble.io
    • Python SDK for a CLI
    • React Native – Sign in with Device
    • iOS – Sign in with Device
    • Flutter – Sign in with Device
  • 📘SDK Reference
    • Web
      • Sign In with Email/Phone Number
        • Customize the Form
        • Checking the email or phone before sending a verification code
        • Sending Code or Link via WhatsApp
        • Styling
        • Older SDK
          • Customize the Form
      • Sign in with Social Login
        • Getting Access Tokens from Social Login Providers
        • Github Instructions
        • Google Instructions
      • Sign In with WebAuthn
        • Register WebAuthn for a logged-in user
      • Sign In with Device
        • Steps for Pop Up Authentication Prompt
        • Advanced Customization for Login Form
        • Advanced Customization for Pop Up Authentication Prompt
      • Getting Access Token and Logged-In User Info
      • Sending Successful Form Submission
      • FAQ & Troubleshooting
    • React Native
      • Installation
      • Sign In with Device
        • Add Email/Phone Verification
        • Authenticate from a Non-Trusted Device
        • Add a new Trusted Device
        • Remove Trusted Device
      • Sign In with Email/Phone Number
      • Getting Stored OAuth Tokens and User Information
      • FAQ
      • Older SDK Versions
        • Sign in with Email/Phone
        • Sending Code via WhatsApp
        • Sign In with Device
          • Authenticate from a Non-Trusted Device
          • Add a new Trusted Device
          • Customization
    • Flutter
      • Sign In with Device
        • Add Email/Phone Verification
        • Authenticate from a Non-Trusted Device
      • Sign in with Email/Phone Number
      • Getting the Logged-in User
      • Getting OAuth Tokens
      • Signing a User Out
    • iOS
      • Sign In with Email/Phone Number
      • Sign In with Device
        • Authenticate from a Non-Trusted Device
        • Push Notification
        • Check if Trusted Device is Enrolled
        • Add a New Trusted Device
        • Remove Trusted Device
      • Older Versions
        • Biometric/Pin
    • Android
      • Sign In with Device
        • Authenticate from a Non-Trusted Device
        • Check if Trusted Device is Enrolled
        • Add a new Trusted Device
        • Remove Trusted Device
        • Customization
      • Sign In with Email/Phone Number
      • Biometric/Pin
        • Advanced Methods
        • Customization
        • Setting Strings
        • Styling
      • Older SDK Version
        • Sign In with Device
          • Authenticate from a Non-Trusted Device
    • Python (for CLI)
    • API for Other Mobile Apps or CLI
      • Verify Email/Phone Number
        • Handling URL Scheme
    • Backend: Handling Response
  • 🛡️ Protecting Your Account
    • Only Allow Your Website/App to Use Your API Key
    • Rate Limit
    • Enable reCAPTCHA to Protect Against Automated Abuse
  • 🗝️ Getting Access Token
    • Cotter's OAuth 2.0 Tokens Specification
    • Getting the Tokens
      • Get Tokens during Authentication
      • Using the Refresh Token
    • Storing and Removing Tokens
    • Renewing Expired Tokens
    • Verifying JWT Tokens
    • Requesting Custom Fields on your JWT Token
    • Older API
      • Using HTTP Requests
      • Getting the Tokens
        • During Authentication
          • During Email/Phone Verification
        • During enrolling Trusted Devices
  • 🔌API Reference
    • User API
      • User Object
    • OAuth Tokens API
      • Verify JWT Token using API (serverless)
      • Requesting Custom Claims on your Access Token
      • Older API
    • OAuth Tokens from Social Login
    • Event Object
    • Reset PIN API
  • Older API
    • Validating Cotter's Identity Token
    • Validating Cotter's Event Response
Powered by GitBook
On this page
  • Step 1: Set Up Deep Linking
  • Step 2: Update your Sign Up Function
  • Option 1: Verifying Before Registering the User
  • Option 2: Verifying After Registering the User
  • 🎉 You're done!
  1. SDK Reference
  2. Flutter
  3. Sign In with Device

Add Email/Phone Verification

Most of the time, it's required for you to check if the user's identifier (their email or phone number) is valid. With Cotter, you can verify your users via email, SMS, or WhatsApp.

Step 1: Set Up Deep Linking

The verification will follow OAuth's PKCE flow which will open an in-app browser where your user can enter the OTP sent to their email/phone.

Pick a unique URL scheme for redirecting the user back to your app after the verification in the in-app browser is successful. For this example, we'll use myexample://auth_callback .

Setup in iOS

Add the following to your ios/Runner/Info.plist.

ios/Runner/Info.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>

	<!-- ADD THE LINES FROM HERE -->
	<key>CFBundleURLTypes</key>
	<array>
		<dict>
			<key>CFBundleTypeRole</key>
			<string>Editor</string>
			<key>CFBundleURLName</key>
			<string>myexample</string> <!-- 👈 Change this to your own URL Scheme -->
			<key>CFBundleURLSchemes</key>
			<array>
				<string>myexample</string> <!-- 👈 Change this to your own URL Scheme -->
			</array>
		</dict>
	</array>
	<!-- TO HERE -->

	<key>CFBundleDevelopmentRegion</key>
	<string>en</string>

Setup in Android

Add the following to your android/app/src/main/AndroidManifest.xml.

android/app/src/main/AndroidManifest.xml
<manifest ...>
    <application ...> 
    ...

    <!-- Add the lines from here -->
    <activity android:name=".CallbackActivity" >
      <intent-filter android:label="flutter_web_auth">
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.BROWSABLE" />
        <!-- 👇 This is for myexample://auth_callback -->
        <data android:scheme="myexample" android:host="auth_callback"/>
      </intent-filter>
    </activity>
    <!-- Until here -->

  </application>
</manifest>

You may need to stop flutter-run and re-run it to see the changes.

Step 2: Update your Sign Up Function

There are 2 ways to do this:

Option 1: Verifying Before Registering the User

This will work the following way:

  1. The user will be asked to verify their email or phone number

  2. If verification successful, we'll create a new User

  3. Then, set up the current device as trusted.

// 2️⃣  Make Sign Up Function
  void signUp(BuildContext context) async {
    try {
      // ❌ Remove this line
      var user = await cotter.signUpWithDevice(identifier: inputController.text);
      
      // ✅ Add the lines from here
      // (1) Verify the user's email
      // (2) Create the user if verification successful
      var user = await cotter.signUpWithEmailOTP(
        redirectURL: "myexample://auth_callback",
        email: inputController.text,
      );
      // (3) Set up the current device as trusted
      user = await user.registerDevice();
      // To here
       
    } catch (e) {
      print(e);
    }
  }
// 2️⃣  Make Sign Up Function
void signUp(BuildContext context) async {
  try {
    // ❌ Remove this line
    var user = await cotter.signUpWithDevice(identifier: inputController.text);
    
    // ✅ Add the lines from here
    // (1) Verify the user's phone
    // (2) Create the user if verification successful
    var user = await cotter.signUpWithPhoneOTP(
      redirectURL: "myexample://auth_callback",
      channels: [PhoneChannel.SMS, PhoneChannel.WHATSAPP], // optional, default is SMS
    );
    // (3) Set up the current device as trusted
    user = await user.registerDevice();
    // To here
     
  } catch (e) {
    print(e);
  }
}
// 2️⃣  Make Sign Up Function
void signUp(BuildContext context) async {
  try {
    // ❌ Remove this line
    var user = await cotter.signUpWithDevice(identifier: inputController.text);
    
    // ✅ Add the lines from here
    // (1) Verify the user's phone
    // (2) Create the user if verification successful
    var user = await cotter.signInWithPhoneOTPViaSMS(
                  redirectURL: "myexample://auth_callback",
                  phone: inputController.text,
                );
    // (3) Set up the current device as trusted
    user = await user.registerDevice();
    // To here
     
  } catch (e) {
    print(e);
  }
}
// 2️⃣  Make Sign Up Function
void signUp(BuildContext context) async {
  try {
    // ❌ Remove this line
    var user = await cotter.signUpWithDevice(identifier: inputController.text);
    
    // ✅ Add the lines from here
    // (1) Verify the user's phone
    // (2) Create the user if verification successful
    var user = await cotter.signInWithPhoneOTPViaWhatsApp(
                  redirectURL: "myexample://auth_callback",
                  phone: inputController.text,
                );
    // (3) Set up the current device as trusted
    user = await user.registerDevice();
    // To here
     
  } catch (e) {
    print(e);
  }
}

Option 2: Verifying After Registering the User

This will work the following way:

  1. The user will enter some identifier (email or phone number), and we'll create a new User with that unverified identifier.

  2. Set up the current device as trusted.

  3. Once the user is logged-in, ask the user to verify their email/phone number

// 2️⃣  Make Sign Up Function
void signUp(BuildContext context) async {
  try {
    var user = await cotter.signUpWithDevice(identifier: inputController.text);
    
    // ✅ Add the line below
    // (3) Verify the user's email 
    user = await user.verifyEmailWithOTP(redirectURL: "myexample://auth_callback");
     
  } catch (e) {
    print(e);
  }
}
// 2️⃣  Make Sign Up Function
void signUp(BuildContext context) async {
  try {
    var user = await cotter.signUpWithDevice(identifier: inputController.text);
    
    // ✅ Add the line below
    // (3) Verify the user's phone 
    user = await user.verifyPhoneWithOTPViaSMS(redirectURL: "myexample://auth_callback");

  } catch (e) {
    print(e);
  }
}
// 2️⃣  Make Sign Up Function
void signUp(BuildContext context) async {
  try {
    var user = await cotter.signUpWithDevice(identifier: inputController.text);
    
    // ✅ Add the line below
    // (3) Verify the user's phone 
    user = await user.verifyPhoneWithOTPViaWhatsApp(redirectURL: "myexample://auth_callback");

  } catch (e) {
    print(e);
  }
}

Make sure that the identifier that you used inside cotter.signUpWithDevice has the correct type. (If the identifier is an email, then use verifyEmailWithOTP, and so on).

🎉 You're done!

You should now be able to enter your email or phone number during the signup process.

PreviousSign In with DeviceNextAuthenticate from a Non-Trusted Device

Last updated 4 years ago

Make sure you followed the guide for . Update your .

, then continue registering the user if verification is successful

, then allow the user to verify their email/phone number later.

📘
Sign In with Device
Sign Up Function that you made on Step 2
Verify the email/phone number first
Finish registering the user first