Ask HN: How to handle KYC for thousands of users?

For one project I would like to do, I will have to handle thousands or probably tens of thousands of users due to Know Your Customer rules because financial transactions will take place.

Right now my approach was to do it manually because of small scale but if I want to go forward I realize this manual work will not make sense in the long run.

So I wonder how do the other companies do it? Like Amazon for example, since they are working with millions of merchants, or Google and their Adsense and Adwords.

I can understand some type of automatization that can use OCR to screen for name, address and crop a picture from ID or passport, possibly require user to submit selfie. But I do not see how that could be used to fill out business details or even verify the validity of submitted images. I can see a person reviewing the submitted scans and provided details and possibly tweak it by communicating with the user or request additional documents. But how do you automatize this? Is it even possible? For example when I request a payment gateway I have to submit my data and person verifies it so it seems even braintree/stripe/... are doing it manually.