Alternativas ao wireframe.cc para Software as a Service (SaaS) com licença de código aberto

• Software as a Service (SaaS)
  Todas as plataformas Windows Mac Linux Android iPhone iPad Android Tablet Web Self-Hosted Software as a Service (SaaS) Firefox PortableApps.com Slack Electron / Atom Shell Trello Microsoft Office Suite Atlassian Stash Google App Engine
• Licença Open Source
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