That's technically correct, but the real cost in using SES here is probably the development time: - store all sent emails - create an interface for business/n

That's technically correct, but the real cost in using SES here is probably the development time: - store all sent emails - create an interface for business/non-devs to view and search past messages If they were using all the functionality of this "free" SMTP approach, that's quite a bit of development + maintenance cost.