[shadowgovt]

They are very similar, but they are subtly different in ways that might matter, depending on what you want to do.

A type is statically-"tagged" data from the typechecker's point of view. Even if `Foo` and `Bar` are two types with the exact same fields, the typechecker won't let you use as Foo as a Bar or vise-versa unless you've explicitly declared that Foos are Bars (via type aliasing or inheritance).

An interface declares a whole category of types that are equivalent: anything with the same "shape" as the interface will count as the interface. So you can pass objects, child objects, objects with additional fields attached, etc. to an interface input; if the thing has the fields the interface cares about, it'll accept it.

Which you want to use depends on what precisely you intend to do, but interfaces are handy in TypeScript where they may be less useful in some other languages because the underlying JavaScript is so "duck-typed" and sloppy on what it means for something to "have a type;" interfaces often model more accurately the behavior of "native" JavaScript functions (that will take an argument, assume it's an object, and just start touching some fields on it without caring whether more fields exist or not).