Alternativas ao Slack para Software as a Service (SaaS) com licença de código aberto

• Software as a Service (SaaS)
  Todas as plataformas Windows Mac Linux Chrome OS Android iPhone Windows Phone Blackberry Blackberry 10 Apple Watch Android Wear iPad Android Tablet Windows S Web Self-Hosted Software as a Service (SaaS) Firefox Safari Oculus Rift HTC Vive Xbox JavaScript Python BSD PortableApps.com Facebook Slack F-Droid Ubuntu Facebook Messenger Chrome Discord Node.JS Microsoft Office 365 Linux Mint Unity .NET Core Telegram Firefox OS Amazon Web Services Redmine Cloudron ZeroNet Microsoft Azure Go (Programming Language) Ruby on Rails Google Play Store Microsoft SharePoint PureOS (Purism) HipChat Kubuntu Yammer WeeChat total.js tibbr Jive Socialcast chatter.com
• Licença Open Source
  Qualquer licença Licença gratuita Licença Open Source Licença comercial