Simple (and fast) Google App-Engine API project to determine the city, coordinates, region (ISO 3166-2) and the ISO 3166-1 alpha-2 country code based on caller's IP address.

May serve as a fallback for your Android applications if the GPS is unavailable (or deactivated).

That App-Engine project expose a simple cloud endpoint:

$ curl https://<projectid>.appspot.com/_ah/api/api/v1/iplocation
{
 "latitude": 40.714353,
 "longitude": -74.005973,
 "country": "US",
 "city": "new york",
 "region": "ny",
 "ip": "31.6.43.126",
}

As a service to the app, App Engine adds some custom headers to every incoming requests:

Country from which the request originated, as an ISO 3166-1 alpha-2 country code. App Engine determines this code from the client's IP address. Note that the country information is not derived from the WHOIS database; it's possible that an IP address with country information in the WHOIS database will not have country information in the X-AppEngine-Country header. Your application should handle the special country code ZZ (unknown country).

Name of region from which the request originated. This value only makes sense in the context of the country in X-AppEngine-Country. For example, if the country is "US" and the region is "ca", that "ca" means "California", not Canada. The complete list of valid region values is found in the ISO-3166-2 standard.

Name of the city from which the request originated. For example, a request from the city of Mountain View might have the header value mountain view. There is no canonical list of valid values for this header.

Latitude and longitude of the city from which the request originated. This string might look like "37.386051,-122.083851" for a request from Mountain View.

Build -> Deploy Module to App Engine...