TLS-RPT
Reports about TLS delivery failures between mail servers.
SMTP TLS Reporting lets domains receive aggregate reports when senders fail to deliver mail over TLS. It is commonly paired with MTA-STS so domain owners can see whether strict transport policies are causing failures.
reading this as teams choosing a transactional API
Judged purely as an API. What the request contract guarantees on retry, how complete the webhook event coverage is, whether suppressions are readable and writable programmatically, and how much the message log retains when something needs debugging in production.
Applied to tls-rpt, that means weighing idempotency keys, webhook coverage, event stream, and operating track record ahead of the rest, against high-frequency programmatic sends where a missed delivery is a product failure.