Description: Pencil Project is a free and open source GUI prototyping and mockup tool. It allows users to create wireframes and prototypes for software interfaces and websites quickly and easily, without programming knowledge.
Type: software
Pricing: Open Source
Description: Pidoco is a web-based wireframing and prototyping tool used to design and prototype user interfaces and applications. It allows users to quickly create wireframes, mockups, diagrams, and interactive clickable prototypes.
Type: software