Alternativer til Mail.be til Software as a Service (SaaS) med open source-licens

• Software as a Service (SaaS)
  Alle 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) JavaScript Python Windows Mobile Java Mobile S60 Android TV Chrome MetaMask Gmail ZeroNet OpenPGP DAVdroid
• Open Source-licens
  Enhver licens Gratis licens Open Source-licens Kommerciel licens