Hotelsbase is the world largest hotel database, of over 500,000 hotels. It lists hotels and their room prices all over the world. Information within the database includes facility information, map co-ordinates, images, address, contact telephone, weather data, price per room and access to tripadvisor ratings. The API exposes this data to developers allowing them to build applications such as hotel search engines. It uses RESTful calls and responses are formatted in XML.