What Apple and Google have developed isn't an app in itself—rather it's an application programming interface (an API), plus some other fundamental technologies, that other apps can plug into.

All that said, a representative from Google and Apple's joint project conceded that any contact-tracing system will have a false-positive rate, just as Covid-19 tests themselves do.

While other companies are building contact tracing apps, the Apple/Google partnership could greatly expand tracing, since: In the U.S., about 81% of us own smartphones, according to a 2019 survey ...

Apple and Google on Friday announced updates to their joint effort in creating software that public health authorities can use to create coronavirus contact-tracing apps for iPhones and Androids ...

Apple and Google said their tool would also constantly run in the background if people opt to use it, logging nearby devices through the short-range wireless technology Bluetooth.

Apple and Google want to develop tech to track the spread of COVID-19 while protecting individuals' privacy. But some states say the restrictive settings may make it harder to find virus hotspots.