Build a Two-Factor Authentication System

User credentials are often leaked or guessed, making password-only authentication unreliable. Two-Factor Authentication (2FA) adds an extra layer of security by verifying users with something they have (like a phone or email access) in addition to something they know (password).

The 2FA system prompts users for a one-time code after entering their credentials. The code can be sent via SMS, email, or generated through TOTP apps like Google Authenticator. After successful verification, users are granted access to the application or platform.

After entering a valid username and password, the user is prompted for a secondary code. Depending on their chosen method (email, SMS, or TOTP app), the code is sent or generated. If validated correctly, the user proceeds to the dashboard; otherwise, access is denied.

• User logs in with valid credentials.
• System prompts for a secondary code (OTP or TOTP).
• User retrieves code via email, SMS, or authenticator app.
• System validates the code before allowing access.
• Failed attempts trigger alerts or cooldowns to prevent brute-force attacks.

• Google Authenticator (TOTP)
• Speakeasy (2FA in Node.js)
• PyOTP for Python
• Twilio SMS API
• SendGrid Email API