Yes I was. The only thing you need to expose to the web is the address to the server. Localtunnel doesn’t hide my port. It literally says on their website:
localtunnel exposes your localhost to the world for easy testing and sharing! No need to mess with DNS or deploy just to have others test out your changes. Great for working with browser testing tools like browserling or external api callback services like twilio which require a public url for callbacks.
I managed to access the website itself remotely, but clicking on the Start button didn’t do anything.