I'm skeptical about a developer who doesn't like JSON, however it's not clear what his reasoning is from this little anecdote. Maybe there's already a large amo

I'm skeptical about a developer who doesn't like JSON, however it's not clear what his reasoning is from this little anecdote. Maybe there's already a large amount of code using the custom method, maybe the data is not that complex and there are layers that don't have ready access to a JSON parser. A lot of the rest of it sounds like simple pragmatism and YAGNI which is something many young and brilliant developers need to learn. That said, if he lets copy and paste code multiply and not be refactored and relies on his perfect memory of the codebase to update multiple places then that could be a red flag. Anyway, if he has the patience so explain the reasoning to you and gives you some war stories I think you'll come out better for having listened.