docker-serveo

https://serveo.net is an alternative for ngrok. taichunmin/serveo can let you secure URL to your localhost server through any NAT or firewall in Docker. And taichunmin/serveo-server can let you host your own serveo. Maintained by taichunmin on GitHub, where it has earned 115 stars from the community.

It's actively developed around alpine, docker, docker-compose, and is a solid reference for anyone building with these tools.