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FlowCryptProton Mail
Freemium

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

 Freemium

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

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

Checked September 24, 2026

Checked September 23, 2026

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