Below is the API for the OCaml standard library. It's directly copied over from the OCaml Manual, formatted to the Reason syntax and styled accordingly. The API docs are work-in-progress; we'll be polishing these gradually!
If you're targeting JavaScript, the API docs for BuckleScript includes all of below, plus JS-specific APIs.
module Opn: sig .. end
val mk : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> ?docs:Docstrings.docs -> ?override:Asttypes.override_flag -> Ast_helper.lid -> Parsetree.open_description