If you want to look-up on HTTP libraries available from the OCaml ecosystem, you should take a look on this great post: Simple, modern HTTP client library? - #14 by edwin
It summarizes available libraries with dependencies and the discussion on this subject is interesting. For the example, I’m more into the idea of having only OCaml dependencies instead of using a C library that may require as much code and dependencies as if it were made in OCaml.
Another point, this time related to the production of a static executable, is that you can currently produce portable and static executables using Esperanto - however, the work required is certainly greater than a simple executable compiled with OCaml and the -static option (this article describes how to do this).