Two of Silicon Valley’s biggest companies are working together on a program aimed at slowing the spread of the coronavirus.

Apple Inc. (Nasdaq: AAPL) and Google Inc. said they are working on contact-tracing technology that will allow users to opt into a system that catalogs other phones they have been near as a way to track the spread of COVID-19.

“All of us at Apple and Google believe there has never been a more important moment to work together to solve one of the world’s most pressing problems,” the companies said in a joint news release. “Through close cooperation and collaboration with developers, governments and public health providers, we hope to harness the power of technology to help countries around the world slow the spread of COVID-19 and accelerate the return of everyday life.”

How the Contact-Tracing Program Works

The program allows mobile phones using both iPhone and Android operating systems to trade information using Bluetooth. Users will receive an alert when they have been close to someone who has tested positive for the COVID-19 virus.

The contact-tracing program is expected to be available in mid-May as a tool available to other apps endorsed by public health officials. Both companies plan to build the technology into their operating systems so that users don’t need to download an app to log nearby phones.

Apple’s Other COVID-19 App

Apple announced a partnership with the White House and Centers for Disease Control and Prevention to create a COVID-19 app.

The app, which is available on Apple’s App Store, contains a screening tool for coronavirus symptoms. It also has up-to-date information about the virus outbreak.

The company also unveiled a website with the same functions. Windows PC, Android and other non-Apple device users can access the website.

The app and the website start with a series of questions about risk factors, recent exposure and symptoms.

Once users answer those questions, they will receive recommendations from the CDC on what they should do next.

The company cautioned that they were not substitutes for guidance from health care professionals.

Neither Apple’s COVID-19 app or contact-tracing software will use the location or identity of users. The tracing app will only capture data about when users’ phones have been near each other. The data is encrypted on the user’s phone, not company data servers.

The companies said GPS location data is not part of the package.

“Privacy, transparency and consent are of utmost importance in this effort, and we look forward to building this functionality in consultation with interested stakeholders. We will openly publish information about our work for others to analyze,” the companies said.