Pencil — open-source GUI prototyping tool

An open-source GUI prototyping tool that’s available for ALL platforms.

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.

The latest stable version of Pencil is 3.0.4 which contains stability fixes and features a visual stencil builder. More details can befound in the releaste notes.