: How do websites such as Groupon or Zillow detect user location? I have noticed that Groupon.com or Zillow.com knows what city I am located in quite reliably and without asking permission. Does

@RJPawlick198

They are most likely using geolocation by IP address or hostname.

There are many services that provide data for this. One that I know of that's easy to use is freegeoip.net. They have an API that you can call 10,000 times per hour to get geolocation data.

For example, if you make an HTTP GET request to freegeoip.net/json/stackoverlow.com, you can get data back in multiple formats. This example returns JSON:

{
"ip": "69.172.201.208",
"country_code": "US",
"country_name": "United States",
"region_code": "NY",
"region_name": "New York",
"city": "New York",
"zip_code": "10004",
"time_zone": "America/New_York",
"latitude": 40.689,
"longitude": -74.021,
"metro_code": 501
}

Vote Up Vote Down