CoronaMelder, developed under the supervision of the Dutch Ministry of Health, Welfare and Sport, is the official coronavirus notification app in the Netherlands. This free app, available on the Android platform, helps the Municipal Public Health Service (GGD) with their source and contact research. It uses Bluetooth to detect when you are near other people who have the app, without collecting any personal or location data. The app sends you a notification if you have been near someone who later turns out to have corona for at least 15 minutes. In addition, if you turn out to be infected yourself, you can use the app to send a notification to people who were near you during the period you were contagious. The app is voluntary and users cannot be traced by the app's developers, the government or other app users.