Ask HN: Almost) Serverless Bank Possible?

I don't see any reason why not.

There are reasons that some people don't trust the cloud but I don't you'd have trouble convincing regulators that it's OK. (e.g. they use GovCloud, Bridgewater does everything in AWS, etc.)

I'm not quite sure what you are asking? Are you asking if a bank/credit union (e.g. Ally, MITFCU) could go serverless? Assuming that is your question, here is my response:

Maybe. Note that there is more to the bank than the customer site. On the backend you have processing of incoming and outgoing ACH/wire transfers, data storage and retrieval for loan origination and collections, ATM processing, processing of branch transactions, and fielding support calls. That's just what I have come up with in the last 30 seconds. I'm sure larger banks do a lot more (e.g. check processing).

All of these systems could, to some extent, be architected around some form of event system that runs functions. That's how some fintech companies approach these problems. If I were making the decision, I would weigh the costs of deployment/management with the potential savings in compute usage. Deploying a single monolith, or a handful of microservices is much easier (to me) than dealing with a plethora of "nanoservices".