Weather App
For this app I used the open source API OpenWeather. Openweather is a small IT company, established in 2014 by a group of engineers and experts in Big Data, data processing, and satellite imagery processing. They do very simple and fast APIs to work with their vast database of weather data, satellite imagery and other environmental data. 1.6 million developers work with their APIs, from individuals and small businesses to enterprises. They process 100,000 calls per sec.