Alternativy GyazMail pro všechny platformy s licencí open source

• Všechny platformy
  Všechny platformy Windows Mac Linux Chrome OS Android iPhone Apple Watch Android Wear iPad Android Tablet Windows S Web Self-Hosted BSD Xfce Haiku PortableApps.com Slack F-Droid Ruby Gmail GNOME Cloudron Amazon Echo (Alexa Voice Service) OpenPGP PureOS (Purism) S/MIME
• Licence Open Source
  Jakákoli licence Bezplatná licence Licence Open Source Komerční licence