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 Cf: sig .. end
val mk : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> ?docs:Docstrings.docs -> Parsetree.class_field_desc -> Parsetree.class_field
val attr : Parsetree.class_field -> Parsetree.attribute -> Parsetree.class_field
val inherit_ : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Asttypes.override_flag -> Parsetree.class_expr -> string option -> Parsetree.class_field
val val_ : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Ast_helper.str -> Asttypes.mutable_flag -> Parsetree.class_field_kind -> Parsetree.class_field
val method_ : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Ast_helper.str -> Asttypes.private_flag -> Parsetree.class_field_kind -> Parsetree.class_field
val constraint_ : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.core_type -> Parsetree.core_type -> Parsetree.class_field
val initializer_ : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.expression -> Parsetree.class_field
val extension : ?loc:Ast_helper.loc -> ?attrs:Ast_helper.attrs -> Parsetree.extension -> Parsetree.class_field
val attribute : ?loc:Ast_helper.loc -> Parsetree.attribute -> Parsetree.class_field
val text : Docstrings.text -> Parsetree.class_field list
val virtual_ : Parsetree.core_type -> Parsetree.class_field_kind
val concrete : Asttypes.override_flag -> Parsetree.expression -> Parsetree.class_field_kind