You're misinterpreting "database". In this case the geoIP database is like a 1MB CSV file, provided for free to the entire world by maxmind (a major network pr

You're misinterpreting "database". In this case the geoIP database is like a 1MB CSV file, provided for free to the entire world by maxmind (a major network provider). You can put give that file to many servers like nginx/apache out of the box, they will start adding a header with the country and the city of the client. What this service is doing is effectively looking up the ip block in that csv file and returning the result as JSON.