I’ve gone through this process for my email client Kanmail [1]. The third party audit is not required for email clients that run on end users computers and store credentials locally. By the looks of it Pegasus falls into this category and should not have any issues getting approved (still need the YT video and such but the Google team are surprisingly responsive and helpful in my experience). [1]... - Source: Hacker News / about 2 years ago

I’m building a desktop email client [0] that has $45 lifetime licenses. Made to scratch my own itch I’ve been using it as my only client for 4 years now, barely makes any money though! [0] https://kanmail.io. - Source: Hacker News / over 2 years ago

I use pyinstaller for my Kanmail email client [1] and it’s fantastic, but at creating Mac app bundles or Windows exes. Tried making actual standalone binaries for another project and, as others have mentioned, they’re incredibly slow to startup. Still, I am a huge fan of the project and it makes it possible to make webview desktop “apps” (like or hate them) with Python. [1] https://kanmail.io. - Source: Hacker News / over 2 years ago

There's pywebview (https://github.com/r0x0r/pywebview/) which is a Python lib that uses whatever native webview implementation exists. Obviously means some compatibility work between each OS, but gives out very small apps what work very well on the whole. I'm using it on my cross platform email client (https://kanmail.io). - Source: Hacker News / over 2 years ago

Polymail - This one is a lot like Twobird but with a lot more features. It's a different type of email client. It's really cool, but the Windows version is just a web app. It's available on iOS as well. Source: over 2 years ago