Green Urban Data (GUD) is creating new tools, using Environmental Big Data and satellite technology, that provide information to solve future ambient problems in cities. This information is given through a simple web viewer that allows an easy understanding of the data rather than complicated tables, graphs and statistics parameters. Our tools allow to consult the environmental information of any city of the world showing up to different indexes such as temperature, quality of vegetation and air quality. GUD manages to monitor the entire city to obtain a sustainable urban environment supporting Smart Cities and being an essential tool for governments and companies that work to improve citizens life quality.