How to Audit API Support for 2FA Login SMS OTP Delivery

Short answer: choose a messaging API by testing whether one app can keep 2FA login SMS OTP traffic separate from subscription renewal notices and an auditable logistics report email. For the report attachment, persist approved bytes before dispatch, give every resend a new attempt ID, and permit cancel only while that attempt is still queued. The deciding constraint is compliance evidence. A delivery result alone cannot show which generated report was approved, which attachment bytes were used, or whether cancellation won a race with dispatch. Those questions need an application-owned record e