Caddy is at the same level as nginx/apache. It is able to do everything a web server is expected to (serving web sites, files and proxying services) plus handling LetsEncrypt automatically. It does not, afaik, do dynamic service discovery like traefik nor load balancing of TCP at the protocol layer, like e.g. haproxy.
https://caddyserver.com/features
We are long-time fans of Caddy, preferring it over traefik + nginx especially for our docker-compose flows.. though it's fair to distinguish 'can' vs 'easy to do'
E.g., we can imagine writing or using a plugin to figure out some upcoming fancy sticky session routing logic based on routes/content vs just the user IP, but there are easier and more 'with the grain' solutions than with what Caddy exposes today, afaict
(Agreed tho: The reverse proxy module, for more typical cases, is awesome and we have been enjoying for years!)
Sticky sessions are supported: https://caddyserver.com/docs/caddyfile/directives/reverse_pr..., and yes it's pluggable so you could write your own LB policy. Very easy, just copy the code from Caddy's source to write your own plugin. Let us know if you need help.
`query [key] ` A+++, I missed when this got added, amazing!
(this basically solves the sticky shared chatroom websocket problem for us when routing to resources with gravity, in our case, multiuser data science notebooks!)
