Marvel is a free prototyping and collaboration tool that lets designers transform their files into interactive, sharable prototypes viewable on any device and get feedback. Marvel wants to solve the problem of how designers and agencies deliver their work to clients and teams. Putting beautiful high-resolution mock-ups and designs into a Powerpoint or Email is no way to win a pitch or showcase work. Marvel enables designers to present and test their work on any device in just a few clicks. Marvel is powered by Dropbox which means prototypes are updated in real-time. The moment people save a PSD, their prototype updates.