ProtonMail is an email service that's known for being privacy-conscious, which makes it popular among users who seek more secure alternatives to Gmail. Thanks to the success of its email service, Proton has since branched out into different verticals, including encrypted contacts, a VPN service, and, most recently, an end-to-end encrypted calendar called ProtonCalendar. In a bid to give users more confidence in its services, Proton has now announced that its ProtonMail app on Android has gone open source and has passed an independent security audit.

In a recent blog post, the company explained why it took the open source route for its ProtonMail apps and wrote, "One of our guiding principles is transparency. You deserve to know who we are, how our products can and cannot protect you, and how we keep your data private. We believe this level of transparency is the only way to earn the trust of our community...To that end, open source has long been a priority at Proton." However, it's worth noting that the ProtonMail Android app isn't the first app from the company to take the open source route.

The ProtonMail web app has been open source since 2015, which was followed by the iOS app last year and the Bridge app last week. The ProtonMail app on Android is the latest to join the list, which means that now all of its ProtonMail apps are out of beta and open source. The company further adds that as part of making its Android app open source, it commissioned an independent security audit from SEC Consult which found no outstanding vulnerabilities in the app. While ProtonMail's decision to go open source won't have any direct effect on users, it will allow third-party security researchers to analyze the code and report any vulnerabilities they might find. You can access the code on ProtonMail's GitHub page and submit your feedback if you happen to find any issues.

Source: ProtonMail blog