Pencil Project Pencil is a standalone app or Firefox extension that lets you create diagrams or UI mockups. It doesn't have collaboration/multi-user features. The Pencil... Free Open Source Mac OS X Windows Linux PortableApps.com Electron / Atom Shell ... Firefox Cliparts Firefox extension Wireframing Add a feature 318 Like
MockingBot 99% free mobile prototyping tool makes it easy to create clickable mobile app prototypes, and collaborate with your team in real time. Commercial $ $ $ Mac OS X Windows Linux No features added Add a feature 0 Like
