[chrizel]

We switched from using SMTP to the AWS SDK for SES because when sending an e-mail the SDK returns the unique message ID of the e-mail. This allowed us to have a special process for handling bounces in our software by using an SNS HTTP endpoint. So the SDK makes sense for use cases where the SMTP protocol doesn't provide enough information.

[wiml]

Hm, many MTAs do return a unique queue ID when they accept a message over SMTP. Does SES not implement that?

[sethammons]

Any examples? Curious how they do it. Just extra info in the 250 OK response to the DATA command?

[mjl-]

Why would the Message-ID (that you assign) not work for this purpose? Perhaps the SNS notification doesn't include the message-id?

[redditor98654]

SES does not allow the caller to set the id of the message and instead assigns one when you make the call.

It is a bit painful for idempotency.

[hardwaresofton]

Thanks for noting this, this is a pretty solid reason — I thought most people tried to correlate other fields on the incoming email but this also makes sense