Pencil: GUI prototyping

Pencil is built for the purpose of providing a free and open-source GUI prototyping tool that people can easily install and use to create mockups in popular desktop platforms (Linux, Max OSX, Windows). Pencil is a good free Microsoft Visio alternative.

    • Easy GUI Prototyping
    • Built-in Shape Collections
    • Diagram Drawing Support
    • Exporting to Different Output Formats
    • Firefox Extension