A fork of @rdegges'ipify with IPv6 support, hosted on Google App Engine
Accessible via http://api.ipify.io and https://api.ipify.io
Feel free to use and abuse.
$ curl 'http://api.ipify.io'2001:0db8:85a3:0000:0000:8a2e:0370:7334
$ curl 'https://api.ipify.io'2001:0db8:85a3:0000:0000:8a2e:0370:7334
$ curl 'https://v4.ipify.io'172.16.0.99
$ curl 'https://v4.ipify.io/?format=json'{"ip":"172.16.0.99"}
$ curl 'https://v4.ipify.io/?format=jsonp'callback({"ip":"172.16.0.99"});
$ curl 'https://v4.ipify.io/?format=jsonp&callback=asdf'asdf({"ip":"172.16.0.99"});
$ curl -v -H'Origin: www.example.com''https://v4.ipify.io/?format=jsonp&callback=asdf'2>&1|egrep -i 'origin'
> Origin: www.example.com< vary: Origin< access-control-allow-origin: www.example.com