Inets_mod_proxy is a project mainly written in Erlang, it's free.
Simple HTTP proxy module for erlang inets httpd service.
This module acts as reverse proxy. It is not package as OTP application, so just drop it in your BEAM load path and use with the following example inets httpd configuration:
[
...
{mod_proxy_target, {https, "server.com", 443},
{modules, [..., mod_proxy, ...]}
...
].