If you use ProtonMail or have been holding off until the secured mail service adds support for email clients like Apple Mail, then you will be pleased to know that the ProtonMail has finally added support for Mail and other apps to its encrypted mail service.
In addition to stock Mail app on the Mac, ProtonMail is also supporting other email clients like Microsoft Outlook and Mozilla Thunderbird. On iOS and Android ProtonMail has released dedicated email apps, so adding support for stock Mail clients is a welcome change in their strategy. The support has been added through ProtonMail Bridge, which is available for download to those with paying ProtonMail accounts.
With ProtonMail Bridge you can access your email account with the stock Mail app on the Mac while still having zero-access encryption and end-to-end encryption ProtonMail is known for. You don’t need to make any change to your email client, since the Bridge will encrypt and decrypt emails in the background for you.
It acts as a local email server that interacts with the Mail app, while the bridge also communicates with the ProtonMail’s encrypted email server. It essentially ‘translates’ what is received from ProtonMail servers in encrypted form in a language that email clients like Mail can understand thus playing a role of a bridge.
You can learn more about ProtonMail Bridge and download it from their official site here.