Any web developer that is writing not just front-end code but also backend services or an APIs should have come across HTTP status codes and know the reason for

Any web developer that is writing not just front-end code but also backend services or an APIs should have come across HTTP status codes and know the reason for their existence. I came across this quite early in my programming career when writing a very basic http service (it's not that long ago, I've been programming for about 10 years) and the first thing you learn are that your HTTP response will usually have headers, a body, and a status code. In my experience, though, when working as a front end developer I've had to deal with developers (mostly in the .Net camp) who will gladly return errors with 200 OK and an xml/json object with the typical "StatusCode: xxx", where XXX is some made up error code that you'll need to reference in their application. I believe this is because many backend developers are in web development by accident, and don't really care much about the web as a platform.