Axure vs Proto.io: What are the differences?
Axure: Create interactive clickable prototypes for Web, Desktop or Mobile applications. The way to plan, prototype, and hand off to developers, all without code. A wireframing, rapid prototyping, documentation and specification software tool aimed at web, mobile and desktop applications; Proto.io: Build high-fidelity fully interactive mobile app prototypes in minutes. Proto.io supports all the major mobile gestures and touch events like tap, tap-hold, swipe, pinch, and zoom. Interaction designers are not limited to a single ‘link’ transition anymore. Instead they can apply animated screen transitions like slide, fade, pop, flip, flow, and turn.
Axure and Proto.io belong to "Interactive Mockups" category of the tech stack.