HAproxy server authorisation using an API or OAuth / JWT tokens.

[wontbeherelong]

I'm using HAproxy as a reverse proxy, using a number of different sub domains. My main domain points to my 'Organizr' instance, and I've been reading this article on severauth: https://docs.organizr.app/books/setup-features/page/serverauth

What I'd like is to use one of the methods given to only allow access to my subdomains if a user is logged in to Organizr, and if not redirect them to my main domain. Examples are given for nginx and caddy, but not for HAproxy. Having gone this far, I'd rather try and do it with HAproxy now (and hopefully learn something).

Can anyone tell me which method(s) are possible in HAproxy, and point me towards any tutorials/further reading? I've had a google and I'm not turning up a great deal, so could do with a nudge.