[francislavoie]

You can do this with Caddy already, with Automatic HTTPS. Caddy will automatically set up its own CA and use it to issue certs (using smallstep) with .local and .localhost domains.

We don't do anything with mDNS though but we've thought about it; none of us use macs anymore but PRs are welcome to make that work. I don't have enough expertise with mDNS to confidently implement it myself, and especially less-so because the implementation would be different on every OS (needs build flags to change the implementation depending on the build target). And this would be free and open source, rather than this paid product.

[qbasic_forever]

On modern systemd-based Linux systems that use its systemd-resolved DNS resolver it automatically forwards all *.localhost traffic to your local host. It works great with caddy for local development and testing of services.

[francislavoie]

Yep! And some browsers now hard-coded resolve *.localhost to ::1 by default, so you often don't need any resolver at all. See https://dev.to/k4ml/firefox-and-chrome-resolve-any-localhost...

[klysm]

I’m initially bothered by browsers doing this but perhaps it’s fine

[throwawaymobule]

<hostname>.local is usually setup if you have an mDNS daemon running. I think Ubuntu does this ootb, and if you still have an old windows install, you may have a copy of 'bonjoir' that was bundled with iTunes.

You could probably lean on existing software to do most of the work.

[francislavoie]

I agree that reaching out to systemd-resolved on Linux and Bonjour on Mac/Windows is probably the way to go, but I don't have the time/energy to learn these APIs and test it right now, hence why I'm asking for help! :)

[WorldMaker]

Windows has had built-in mDNS (and DNS-SD) support built-in since Windows 10, I wouldn't recommend using Bonjour on Windows today.

That said, the tricky part to Windows' mDNS support is that the APIs to work with it are WinRT-only and you'll need a WinRT projection of one sort or another to use them.