Balsamiq - Balsamiq. Rapid, effective and fun wireframing software.
UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.
Moqups - The most stunning HTML5 app for creating resolution-independent SVG mockups, wireframes & interactive prototypes for your next project
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
Invision - Prototyping and collaboration for design teams
Axure - The most powerful way to plan, prototype and hand off to developers, all without code. Download a free trial and see why professionals choose Axure RP 9.