When you make an SSH connection to serveo.net and request remote forwarding, a subdomain is assigned, and traffic to that address is forwarded to your local server (like ngrok).
Use it like this: ssh -R 80:localhost:8080 serveo.net
The main difference is the use of the SSH client, so there's nothing to install.
Like ngrok, it can also do HTTP inspection and replay using a terminal GUI launchable after SSH is connected.
