In our UI/UX design guide we told you about UI software prototyping. In a nutshell, there are 5 types of prototyping, and each type has its own set of digital (and not only) tools that fits best the process. Some of them quite famous, some – not. Today we are ready to present you the ultimate list of UI prototyping tools. Unbiased as always, Syndicode tried to collect the most popular of them.