Mockup.io is described as 'web-based service to share, present, discuss and test your mobile app mockups and prototypes' and is an app in the Development category. There are six alternatives to Mockup.io for a variety of platforms, including Online / Web-based, iPhone, Android, iPad and Mac. The best alternative is Origami Studio, which is free. Other great apps like Mockup.io are Adobe Comp CC (Free), Principle (Paid), Threed.io (Free) and Fluid UI (Freemium).
Origami Studio is a free design tool built by Facebook designers for creating interactive UI prototypes. An elegant, layer-based interface allows designers to repaidly create prototypes with layers, build interactions and then share them with others.
Comp CC makes it easy for designers to lay out ideas with real assets like photos, text and shapes. They can then send the wireframe to Photoshop CC, Illustrator CC, InDesign CC or Muse CC to refine and finish.
Principle makes it easy to create animated and interactive user interface designs. Whether you're designing the flow of a multi-screen app, or new interactions and animations, Principle lets you create designs that look and feel amazing.
Upload your designs,mockups or wireframes and organize them in projects. Share them with friends, colleagues and clients to get point specific Feedback. Giving Design Feedback is easy possible without any registration by your customers. You can Upload Images and Multipage PDFs