Public IP Address API with two lines of Nginx config

By Enzo Calamia

Here is how I set up a "show my public IP address" with Nginx without any backend (no PHP, no Nginx-Lua, ...).

The following block does the trick:

location /ip { default_type text/plain; return 200 $remote_addr; }

The response is simply the IP address of the client:

$ curl https://example.com/ip 2001:1b48:103::189

The default_type text/plain directive has no utility other than preventing Web browsers from attempting to download the response as a file. That is, a Web browser can display the IP address directly.

For programs interacting with the endpoint, it has no particular utility.

Bonus: JSON response

Want a JSON response? Sure, it is perfectly doable:

location /json_ip { default_type application/json; return 200 "{\"ip\":\"$remote_addr\"}"; }

The response is now a pretty JSON document:

$ curl -s https://example.com/json_ip | jq { "ip": "2001:1b48:103::189" }

I hope that little Nginx trick will save you some maintenance time.