Difference between a programmer, developer, and engineer

However you try to categorize, most corporations treat all three interchangeably. Most non-technical people see no difference between the three.

Differences start to show when you analyze how corporations treat their people. Most corporations will only use one term to describe all their actively programming IT staff which usually will reflect how corporation thinks of their role.

I always half-joke that I have a master's degree in computer science and I don't know the difference between those, as in two years out of school nobody cares and they are almost synonymous (exception: in some countries like Canada you can't in theory call yourself engineer if you don't have such designation, official tests and all).