The use of Internet-of-things (IoT) applications (solutions) in the real world has increased exponentially. In smart cities, networked IoT devices are collecting data from the physical medium to optimize the decisions to improve city services to citizens. One way to evaluate this services solution is the use of the living labs, shown as a good option to evaluate previous real applications. However, when this is implemented in the real-world cases, most of them are no scalar to the complexity of the city. One of the factors is that it is assumed an IoT infrastructure designed to meet the properties of the scalability for a smart city. This article proposes a validation methodology for the scalability compliant infrastructure: modularity, interoperability, and resiliency properties. The proposed methodology is based on the best practices achieved during a living lab of the Smart Cities Innovation Center in the Universidad de Guadalajara implementation.