OpenAPI's 'type system' is surprisingly advanced also, supporting explicitly discriminated unions and other things like that, which doesn't model well into all other languages.
I believe recent versions of OpenAPI are "compatible" with JSON Schema (at least they "wanted to be" last I checked as I was implementing some schema converters).
Even TypeScript is not enough to represent all of JSON Schema! But it gets close (perhaps if you remove validation rules and stuff like that it's a full match).
But even something like Java can represent most of it pretty well, specially since sealed interfaces were added. I know because I've done it :).
I believe recent versions of OpenAPI are "compatible" with JSON Schema (at least they "wanted to be" last I checked as I was implementing some schema converters).
Even TypeScript is not enough to represent all of JSON Schema! But it gets close (perhaps if you remove validation rules and stuff like that it's a full match).
But even something like Java can represent most of it pretty well, specially since sealed interfaces were added. I know because I've done it :).