RingCaptcha offers phone 2FA, OTP, SMS, voice API to help companies verify, engage, and retain end-users - 'Real Users, Real Contact'. With RingCaptcha, you integrate once with us and gain access to the best routes for sending OTP or SMS notifications reliably through Twilio, MessageBird, Infobip, Nexmo, etc., RingCaptcha builds additional security and reliability layer on top of all global and regional OTP & SMS providers to mitigate against fraud using machine-learning, and reliably send OTPs and SMS notifications through best routes chosen based-on real-time data, as well as auto-resend through alternative routes to further increase reliability. With our OTP & SMS marketplace, you get the best price with no provider lock-in. Best of all integration is a breeze - just cut-and-paste some code or call our single REST API endpoint.