: This is the most prominent unofficial client. It is Electron-based and available for Windows, macOS, and Linux. Its releases often include "portable" versions (like files that run without installation on Windows). PortableApps.com : Community requests have been made for a PortableApps version
If you prefer a truly portable experience, you can use a portable version of a traditional email client like Thunderbird Portable The Catch: This requires Proton Mail Bridge , which itself requires an installation and a paid Proton plan Desktop App Features at a Glance proton mail desktop app portable
The demand for a portable version stems from several legitimate use cases: : This is the most prominent unofficial client