Prototyping Software

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  Pencil Project 3.1.0Free

  A free and open-source GUI prototyping tool.

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  Adobe XDFree to try

  Create and share designs for websites, mobile apps, and other user experiences.

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  WireframeSketcher 6.4.2Free to try
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  Mockuuups StudioFree to try

  Drag-and-drop tool for creating beautiful app previews or any marketing materials.