Try to call the erlang function :inet.getif()

Something like this should do the trick

{:ok, ifs} = :inet.getif()
ips = Enum.map(ifs, fn {ip, _broadaddr, _mask} -> ip end)

I think getif is not documented, so technically it could disappear eventually. getifaddrs may be a more future-proof option. Note in practice this will return multiple IPs since you’ll have at least a loopback and an external IP.

You’ll find more options if you google something like “erlang get ip”, whatever works in Erlang will also work in Elixir.

If anyone else is looking for it’s own IP address and finds this thread… In my nerves project I use :inet.getif/0 and loop through the result until I find one that fits my pattern (e.g. one that starts with 192.168).