Currently, the Auth0 Forms OTP verification template treats the input field as a numeric data type. This inherently drops leading zeros when referencing the field (e.g., fields.verification_code) in downstream flows. While Auth0’s internal OTP generation circumvents this by exclusively using digits 1-9, this strict numeric typing severely restricts integrations with external custom phone providers (such as Twilio), which frequently generate OTP codes containing zeros. The current recommended workaround—switching to a standard text field—significantly degrades the end-user experience, particularly on mobile devices. Standard text fields accept alphanumeric input but do not reliably trigger the native numeric keypad. We request a dedicated input field configuration that strictly validates and formats for numeric input (ensuring mobile numeric keypads are triggered) but processes and stores the resulting value as a string to safely preserve leading zeros.
We are utilizing a Custom Phone Provider for OTP generation to optimize third-party billing (incurring costs only on successful verifications rather than upon generation). To reliably process these external OTP codes without dropping leading zeros, we require an input field that supports string outputs. Implementing this feature will prevent critical user sign-up failures, eliminate the need for suboptimal text-field workarounds, and ensure a seamless, mobile-optimized authentication experience for our customers.