Choose the API that lets your application prove what it intended to send, cancel an obsolete SMS, and observe delivery without making provider state your audit record. For an edtech backend sending a generated report as an attachment, I would start with an application-owned evidence ledger and use SMS polling as an observation mechanism. Add email escalation only when its polling delay is acceptable.

This decision is about evidence, not a feature checklist. A useful record can answer four questions: who authorized the report, which recipient policy applied, whether the reminder was still relevant, and what delivery state the system observed. The provider is one witness in that record.

Infrai fits the SMS leg when that evidence ledger should sit behind a stable REST contract.…