The VisionMobile Q1 2015 Developer Economics survey found that 53 percent of mobile development professionals say they are actively working on Internet of Things (IoT) projects. However, for 30 percent, IoT is just a hobby, and for 20 percent, it is a side project. Still, the report projects that there will likely be 4.5 million IoT developers, paid or unpaid, by 2020.
The most common types of IoT projects are smart home devices (37 percent of developers surveyed) and wearables (35 percent of developers surveyed).