Twilio User Authentication & Identity

Twilio User Authentication & Identity, delivered through the Twilio Verify API, helps businesses confirm that the person registering or signing in is a legitimate user rather than a fraudster or an automated script. It provides one-time passcode delivery and multi-factor authentication across a wide set of channels — SMS, voice call, email, WhatsApp, push notification and time-based authenticator apps — through a single API, so developers implement one integration and let the service handle channel selection, message delivery, retry logic and code validation. That matters more than it sounds: building reliable global OTP delivery in-house means managing carrier relationships, sender identities, localisation, delivery rate optimisation and regulatory requirements in every market, all of which the platform absorbs.

The identity and anti-fraud layer is where the product goes beyond simple passcodes. Silent network authentication verifies a user's phone number directly with the mobile carrier in the background, confirming possession of the device without the user ever entering a code — the lowest-friction verification available, and increasingly the preferred path where supported. Lookup capabilities return line type, carrier, portability and risk signals about a phone number before a message is sent, allowing a business to reject known-disposable virtual numbers at signup rather than discovering the problem later. Fraud Guard protects against SMS pumping, an attack in which fraudsters trigger huge volumes of verification messages to premium-rate numbers to harvest carrier revenue, which can cost an unprotected business very large sums quickly. Adaptive logic allows verification requirements to vary with assessed risk, keeping friction low for ordinary users while escalating for suspicious attempts. Global reach, localisation of message content, and compliance with regional telecommunications rules are handled by the platform. Usage-based pricing starts from around USD 0.05 per verification with no subscription minimum, a free trial available and no free version, making it accessible from prototype to very high volume.