The highly heterogeneous environment of IoT (Internet of Things) and Smart cities guarantees that every stakeholder's requirements can be achieved and implemented. However deciding which is the most appropriate sensor to adopt among various similar ones and, even most important, how to use it is not an easy task; a task that, as of today, cannot be done without access to source code or documentation. Moreover heterogeneity in descriptions and definitions complicate sensor interfaces comparison and selection, and may create interoperability and portability problems among multiple providers. In this work we aim at providing a Q&A tool that guides the user in the production of a RESTApi sensor's interfaces according to the OpenAPI specification. The automatically produced ad-hoc specification is used as a base for defining sensors' interfaces equivalence and similarity using natural language processing techniques.