Thanks for putting this together and documenting it so well. I’ve had to build this solution twice now, and far less elegantly.

The S3 PUT charges caught me off guard the first time (receiving lots of marketing/spam email will cost $1/1000 emails). I ended up putting small emails up to 400 kB in dynamoDB and only using S3 for large emails and attachments, which could be a means of cost reduction in this solution as well.