Nice article. I am a little dubious of the claim that interfaces in Go are somehow different than in other languages. Or at least not for the reasons you stated…. The only noticeable difference (to me) between interfaces in Go and interfaces in Java (for instance) is that in Go, a struct doesn’t need to explicitly declare that it implements a given interface(s). This is its own special kind of useful because it means new interfaces can be created for existing types.