For HTTP I always use 'ocaml-cohttp' (opam install cohttp): https://github.com/mirage/ocaml-cohttp/blob/master/examples/async/hello_world.ml https://github.com

For HTTP I always use 'ocaml-cohttp' (opam install cohttp): https://github.com/mirage/ocaml-cohttp/blob/master/examples/async/hello_world.ml https://github.com/mirage/ocaml-cohttp/blob/master/examples/... For JSON I normally use 'Jsonm' but I've heard good things about 'Ezjsonm': https://github.com/samoht/ezjsonm https://github.com/samoht/ezjsonm I've not personally tried them but 'postgresql-ocaml' and 'ocaml-memcached' look plausible.