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 module Scanning : sig type in_channel type scanbuf = Scanf.Scanning.in_channel val stdin : Scanf.Scanning.in_channel type file_name = string val open_in : Scanf.Scanning.file_name -> Scanf.Scanning.in_channel val open_in_bin : Scanf.Scanning.file_name -> Scanf.Scanning.in_channel val close_in : Scanf.Scanning.in_channel -> unit val from_file : Scanf.Scanning.file_name -> Scanf.Scanning.in_channel val from_file_bin : string -> Scanf.Scanning.in_channel val from_string : string -> Scanf.Scanning.in_channel val from_function : (unit -> char) -> Scanf.Scanning.in_channel val from_channel : Pervasives.in_channel -> Scanf.Scanning.in_channel val end_of_input : Scanf.Scanning.in_channel -> bool val beginning_of_input : Scanf.Scanning.in_channel -> bool val name_of_input : Scanf.Scanning.in_channel -> string val stdib : Scanf.Scanning.in_channel end type ('a, 'b, 'c, 'd) scanner = ('a, Scanf.Scanning.in_channel, 'b, 'c, 'a -> 'd, 'd) Pervasives.format6 -> 'c exception Scan_failure of string val bscanf : Scanf.Scanning.in_channel -> ('a, 'b, 'c, 'd) Scanf.scanner val fscanf : Pervasives.in_channel -> ('a, 'b, 'c, 'd) Scanf.scanner val sscanf : string -> ('a, 'b, 'c, 'd) Scanf.scanner val scanf : ('a, 'b, 'c, 'd) Scanf.scanner val kscanf : Scanf.Scanning.in_channel -> (Scanf.Scanning.in_channel -> exn -> 'd) -> ('a, 'b, 'c, 'd) Scanf.scanner val ksscanf : string -> (Scanf.Scanning.in_channel -> exn -> 'd) -> ('a, 'b, 'c, 'd) Scanf.scanner val kfscanf : Pervasives.in_channel -> (Scanf.Scanning.in_channel -> exn -> 'd) -> ('a, 'b, 'c, 'd) Scanf.scanner val bscanf_format : Scanf.Scanning.in_channel -> ('a, 'b, 'c, 'd, 'e, 'f) Pervasives.format6 -> (('a, 'b, 'c, 'd, 'e, 'f) Pervasives.format6 -> 'g) -> 'g val sscanf_format : string -> ('a, 'b, 'c, 'd, 'e, 'f) Pervasives.format6 -> (('a, 'b, 'c, 'd, 'e, 'f) Pervasives.format6 -> 'g) -> 'g val format_from_string : string -> ('a, 'b, 'c, 'd, 'e, 'f) Pervasives.format6 -> ('a, 'b, 'c, 'd, 'e, 'f) Pervasives.format6 val unescaped : string -> string end