Wireflow is an open-source collaborative tool for designing and visualizing user experience flows and wireframes directly in the browser, aimed at UX designers, product managers, and developers who need to map out interactive user journeys without heavy graphic design tools. Unlike static flowchart apps, Wireflow’s interface focuses on quick and intuitive creation of flow diagrams that represent screens and transitions, helping teams prototype and iterate on navigation logic and interaction...
The Pencil Project's unique mission is to build a free tool
...Starting from 2.0.2, Pencil is shipped with Android and iOS UI stencils pre-installed. This makes it even easier to start protyping apps with a simple installation. Starting from 2.0.2 Pencil has even more shape collections included by default. The list of built-in collections now includes general-purpose shapes, flowchart elements, desktop/web UI shapes, Android and iOS GUI shapes.