I am wondering if it’s possible to share an app, still in dev, with an URL/QR - outside the own network.
yes it is.
there are a couple ways you can do this:
if you publish your project, you can just share that URL. these URLs look like this:
if you are working on it, you can share the tunnel or LAN URL.
These URLs would look like:
the tunnel URLs will work for anyone assuming your computer is on and the project is open and the tunnel is successfully setup.
the LAN URLs will only work for people on the same wifi network as your computer, but things will load faster since all the code won’t need to go through the tunnel.