This is a simple room alias proxy that can respond to the federation alias query endpoint. The purpose is to allow creating room addresses with vanity domains without having to run a full-blown Matrix homeserver.
Discussion room: #maunium:mau.dev
You can either build the Go program yourself (just git clone + go build),
or use the docker image dock.mau.dev/tulir/mauliasproxy.
After that, copy example-config.yaml to config.yaml
and fill out the details you want. If using docker, mount the directory with
config.yaml at /data.
Finally set up your reverse proxy to proxy /_matrix/federation/v1/query/directory
(and optionally /.well-known/matrix/server) on the alias domains to mauliasproxy.