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.
sig val implementation : Lexing.lexbuf -> Parsetree.structure val interface : Lexing.lexbuf -> Parsetree.signature val toplevel_phrase : Lexing.lexbuf -> Parsetree.toplevel_phrase val use_file : Lexing.lexbuf -> Parsetree.toplevel_phrase list val core_type : Lexing.lexbuf -> Parsetree.core_type val expression : Lexing.lexbuf -> Parsetree.expression val pattern : Lexing.lexbuf -> Parsetree.pattern end