I think it might mean things to different companies, but in most places I've worked, there's definitely a feeling that either front-end or back-end developers s

I think it might mean things to different companies, but in most places I've worked, there's definitely a feeling that either front-end or back-end developers should try to limit how much they modify "the other sides" code. It isn't just a question of capability, if your organization is set up with front-end and back-end developers Conway's law is going to result in a fairly separate front end and back end world that is worked on almost exclusively by the "right" kind of developer - similarly to how most developers will stop designing anything as soon as someone with "Design" in their title joins the company.