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A lightweight Flutter package for sending and verifying email-based One-Time Passwords (OTP) to streamline user authentication. It enables quick integration of email OTP flows with minimal setup, supporting multiple platforms including Android, iOS, macOS, Windows, and Linux. The package handles the backend communication for OTP generation and validation, reducing development time for secure login systems. Ideal for apps requiring secure, passwordless sign-in or account verification.
Use cases
Passwordless login
Account verification
Secure user authentication
Two-factor authentication
Resetting forgotten passwords
Key features
Simple OTP generation
Email-based verification
Cross-platform support
Minimal boilerplate code
Easy integration with Firebase or custom backends
Suitable for
Developers building secure authentication
Apps needing fast OTP workflows
Projects using email as primary identity
Startups prioritizing rapid feature deployment
Teams avoiding complex auth infrastructure
Considerations
Requires a backend service for OTP handling
Dependent on reliable email delivery
Not suitable for high-volume transactional emails
May need rate limiting in production
User experience depends on email provider reliability
Original README
Original README snapshot from the linked source repository. Visit the repository for the latest content.
Email OTP is a Flutter package designed to simplify email authentication using one-time passwords (OTPs). With Email OTP, you can effortlessly generate OTPs and send them to users' email addresses, ensuring secure identity verification. This package offers an efficient and secure method for incorporating email-based OTP authentication into your Flutter applications.
emailPort: The port number used by the SMTP server. Supported values include:
EmailPort.port25
EmailPort.port465
EmailPort.port587
EmailPort.port1025 (For MailHog/Local Testing)
secureType: The type of security used by the SMTP server. Supported values include:
SecureType.none
SecureType.tls
SecureType.ssl
username: The username for your SMTP server account.
password: The password for your SMTP server account.
By configuring these parameters, you can ensure that your application is able to send OTP emails securely and efficiently.
Themes
Theme
Theme Preview
EmailTheme.v1
EmailTheme.v2
EmailTheme.v3
EmailTheme.v4
EmailTheme.v5
EmailTheme.v6
EmailTheme.v7
EmailTheme.v8
EmailTheme.v9
EmailTheme.v10
Template (Optional)
You can also customize the email 🌐 template used to send the OTP. Use the setTemplate method to provide your own HTML template.
voidmain() {
EmailOTP.config();
EmailOTP.setTemplate(
template: '''
<div style="background-color: #f4f4f4; padding: 20px; font-family: Arial, sans-serif;">
<div style="background-color: #fff; padding: 20px; border-radius: 10px; box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);">
<h1 style="color: #333;">{{appName}}</h1>
<p style="color: #333;">Your OTP is <strong>{{otp}}</strong></p>
<p style="color: #333;">This OTP is valid for 5 minutes.</p>
<p style="color: #333;">Thank you for using our service.</p>
</div>
</div>
''',
);
}
Parameters
template: A string containing the HTML content of your custom email template. Use placeholders such as {{appName}} and {{otp}} to dynamically insert the application name and OTP respectively.
By configuring these parameters and using a custom template, you can ensure that your OTP emails are tailored to match your application's branding and style.
Sending OTP
To 📧 send an 🔐 OTP to a user's email address, use the sendOTP method. This method takes the recipient's email address as a parameter.
bool isSent = awaitEmailOTP.sendOTP(email: emailController.text);
if (!isSent) {
print(EmailOTP.lastError); // Prints specific error (e.g. SMTP Auth failed)
}
Parameters
email: The recipient's email address where the OTP will be sent.
Resending OTP
If a user requests a new OTP because they didn't receive the first one, you can use resendOTP instead of generating a new one. This will re-send the existing valid OTP. If it has already expired, a new one will automatically be generated.
EmailOTP.resendOTP(email: emailController.text);
Verifying OTP
To verify an 🔐 OTP entered by the user, use the verifyOTP method. This method takes the OTP entered by the user as a parameter and returns a boolean indicating whether the OTP is correct.
EmailOTP.verifyOTP(otp: otpController.text)
Parameters
otp: The OTP entered by the user.
Get OTP
This code will print the OTP generated by the getOTP() method.
print(EmailOTP.getOTP());
Is Expired
This method will helps you to validate your otp expiry time.