These data are from an innovative survey across seven European countries, revealing, for the first time, the extent and characteristics of crowd workers in Austria, Germany, Italy, the Netherlands, Sweden, Switzerland and the UK. In the associated report, the survey results are complemented by in-depth interviews with a range of crowd workers, shedding light on the realities of their working lives, including the stresses, fears and health hazards they face, as well as the satisfactions they experience. This joint research project, which is ongoing, was launched in January 2016. It is being carried out by the University of Hertfordshire in association with the Foundation for European Progressive Studies (FEPS) and UNI Europa, the European services workers union. Co-funding for national surveys was provided by the Trade Union Unionen in Sweden, the TNO Research Institute in the Netherlands, The Chamber of Labour (AK) in Austria, the Trade Unions Ver.di and IG Metall in Germany, the Trade Union syndicom in Switzerland and the Fondazione EYU in Italy. Fieldwork for the surveys in these seven countries was carried out by Ipsos MORI between January 2016 and April 2017.