Transactional sends through SESv2 SendEmail, on the environment's credentials. A 4xx is EMAIL_SEND_REJECTED: definitely not accepted. A 5xx, timeout, lost response or missing message id is EMAIL_SEND_IN_DOUBT: SES may have accepted it.
SendEmail
EMAIL_SEND_REJECTED
EMAIL_SEND_IN_DOUBT
Static
The process client, on the ambient region and credentials.
Sends one message; every to address sees the others. Returns SES's message ID.
to
Transactional sends through SESv2
SendEmail, on the environment's credentials. A 4xx isEMAIL_SEND_REJECTED: definitely not accepted. A 5xx, timeout, lost response or missing message id isEMAIL_SEND_IN_DOUBT: SES may have accepted it.