CovidWatcher is a research tool built by Columbia University. Information gathered through a mobile app and anonymous online surveys will help crowdsource valuable information about the pandemic, such as potential hotspots and what resources are needed in which neighborhood. This information can help prepare cities, public-health officials, and healthcare institutions in their response to COVID-19, as well as inform individuals about their communities. Participants can download the app (available on iOS App Store and Google Play) or take surveys on our website.