Internet protocols (http, cgi, email etc.) and helper data structures
(mail messages, character sets, etc.)

Ocamlnet is an enhanced system platform library for Ocaml. As the name
suggests, large parts of it have to do with network programming, but it is
actually not restricted to this. Other parts deal with the management of
multiple worker processes, and the interaction with other programs running
on the same machine. You can also view Ocamlnet as an extension of the system
interface as provided by the Unix module of the standard library.