I recently released a cookie library. It can parse and create cookie headers (list((string, string) which both Cohttp and Httpaf uses), both Set-Cookie and Cookie so it works on both client and server. It should be compliant with https://tools.ietf.org/html/rfc6265 and I have a pretty good test suite for the parsing of cookies at least.
I couldn’t find a standalone library before this so I decided to create one since I need it for my web framework, Morph.
The next step is to create and publish integrations with ocaml-session which I have started.
Repo: https://github.com/ulrikstrid/ocaml-cookie
Docs: https://ulrikstrid.github.io/ocaml-cookie