Nice. This looks promising. Very clean API. I like the focus on a narrow use case. Do you have any information on security topics like using TLS, client authentication, etc?
Currently we think this kind of security can be enabled by a simple nginx setup, allowing autorefesh of certificates easily (e.g. certbot). But in the future we will probably handle that in the engine itself.
I've no issue with offloading SSL to a different process though, I tend to prefer doing that anyway a lot of the time.