> I don't think I'm suddenly going to accept that the data presented to my function is valid and fit for purposes just because it goes through someone's JSON sc

> I don't think I'm suddenly going to accept that the data presented to my function is valid and fit for purposes just because it goes through someone's JSON schema library. That's just passing the responsibility on to a third party, which feels lazy and dangerous to me. The purpose of a schema isn't to ensure that every business rule is satisfied. It's just the first step of data validation. It's step 1 of input triage. It's saying, "I'm not even going to look at your input until you can demonstrate that the request meets the minimum requirements of a theoretically valid request." If I'm asking for a Student, and I say they have to have a StudentId, a FirstName, a LastName, and a DateOfBirth, then I can put that into a schema and immediately reject any submission that tries to submit Surname or GivenName. I can go further and say that StudentId is up to 25 characters and can't be blank. DateOfBirth has to be present, must be a date in yyyy-MM-dd format, and it must be in the past, etc. You can reject the data as incomplete or invalid at a glance. You're setting up a basic set of rules that allows you to instantly discard a whole range of invalid input.