Toward reducing barriers for developing applications for the Internet of Things, researchers have connected things to the web enabling the development of IoT mashups. While establishing a Web of Things for mashup development has been
an important step forward, we believe that web-centric IoT toolkits have the potential to increase the use of Internet-enabled things further by increasing the pool of developers and applications that can take advantage of the connected physical world. In this paper we derive several key requirements for IoT
mashup toolkits based on existing systems, past research and our experience with an IoT mashup toolkit called the Web of Things Toolkit (WoTKit). Unlike other systems, the WoTKit aims to address key requirements for IoT mashup developers in one system. From this experience we derive key lessons learned for
the community toward improving toolkits for developing IoT mashups.