A worldwide race. Researchers and technologists in these days are scrambling to build apps that alert users when they have come into contact with people infected by coronavirus, as governments weigh up how to safely transition out of national lockdowns in the months ahead. Numerous mobile apps are being developed to enable the so-called contact tracing, namely, in a nutshell, the possibility for people to take preventive action and immediately exchange proximity and location data, in order to notify someone who has recently been near to an infected individual, by means of smartphones’ “virtual handshaking”.