TL;DR: For a logistics password-reset fallback, keep the template version and the entire short-lived challenge lifecycle in the application; use email only to deliver either a code or a single-use link when SMS is unavailable. A code is preferable when a depot operator commonly opens mail on a s...
Source: [Dev.to](https://dev.to/arthurfinley2291/email-fallback-for-login-otp-implementing-4-controls-when-sms-is-unavailable-in-go-1c8b)