Use it from the command line
curl ip.uk.app
curl ip.uk.app/json
curl -4 ip.uk.app
curl -6 ip.uk.app
wget -qO- ip.uk.app
(Invoke-RestMethod ip.uk.app/ip) # PowerShell
Use -4 for IPv4 or -6 for IPv6. The /json endpoint returns JSON; /ip returns plain text.
Plain HTTP works too, so it runs on minimal systems without CA certificates. Requests from command‑line tools get plain text automatically. Browsers get this page.
Public vs private IP addresses
The address above is how the rest of the internet sees you. Devices inside your home use private addresses (192.168.x.x, 10.x.x.x or 172.16–31.x.x) that only work on your local network. Your router translates between the two. That is why you need port forwarding before anyone outside can reach a server at home.
Running a server at home?
You need three things: a public IP address (check you are not behind CGNAT), a forwarded port, and a name that follows your IP when it changes. The uk.app home server guide walks through all three.
Frequently asked questions
Is my public IP address the same as my computer’s IP?
Usually not. Your computer has a private address such as 192.168.1.20 on your home network. Your router shares one public address, the one shown above, with every device in the house.
Why does my IP address change?
Most UK broadband and mobile providers assign dynamic addresses. They can change when the router restarts, after an outage or on a schedule. Dynamic DNS keeps a host name pointing at your current address automatically.
Can I get my IP from a script?
Yes. curl ip.uk.app returns just the address as plain text, and curl ip.uk.app/json returns JSON. Both are free for reasonable use.
Why do I see an IPv4 address when I have IPv6?
ip.uk.app works over both IPv4 and IPv6. Your browser picks one, usually IPv6 when your connection has working IPv6. If you still see IPv4, your network or router has no IPv6. From a terminal you can ask for each one: curl -4 ip.uk.app or curl -6 ip.uk.app.
Does a VPN change the IP shown here?
Yes. With a VPN or proxy switched on, you will see the VPN server’s address rather than your own.
