Alternativa ZeroMailu za Software as a Service (SaaS) z licenco odprtokodnega vira

• Software as a Service (SaaS)
  Vse platforme Windows Mac Linux Chrome OS Android iPhone Android Wear iPad Android Tablet Kindle Fire Windows S Web Self-Hosted Software as a Service (SaaS) PHP Windows Mobile Java Mobile S60 Android TV Chrome OpenPGP S/MIME DAVdroid
• Open Source licenca
  Vsako dovoljenje Brezplačna licenca Open Source licenca Trgovsko dovoljenje