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Proton MailFlowCrypt
Freemium

Free accounts work in the mobile and web apps; the desktop apps are offered as a free…

 Freemium

Free extension for individuals, with paid business plans listed on the pricing page.

Windows, macOS, Linux, Android, iOS, Web Browser extension
  • End-to-end encrypted email by default
  • Apps for iOS, Android, macOS, Windows, Linux and the web
  • Works inside the normal Gmail interface
  • Encrypts both messages and attachments
  • Only works with a Proton account
  • Desktop apps need a paid plan after the trial
  • Built around Gmail rather than other mail providers
  • Business features require a paid plan
Downloadable app, Web application, Hosted service Browser extension
Closed source Closed source
License not stated License not stated
Account needed Not stated if an account is needed
Not stated if it works offline Needs internet

Checked September 23, 2026

Checked September 24, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.