Modern smart grids have a complex cyber–physical structure with distributed smart entities and security mechanisms. The application of Internet of things (IoT) technologies can be useful for optimizing the smart grid operation and providing immunity against different cyber-attacks. In this paper, a step-by-step smart modular and scalable design of distribution smart grids is introduced. The proposed plug-and-play procedure enables providing the desired interchangeability for lines/zones inside a distribution network (DN). Thus, keeping DN reconfiguration resilient necessitates the possibility of connecting/disconnecting switches wherever needed inside DN. Therefore, each branch in the DN is equipped by a smart switch that can be remotely controlled via a centralized power IoT platform. The proposed framework, using recent metaheuristic techniques, employs DN reconfiguration for smart grid operation optimization. Most practical issues such as line cost and line parameters are taken into consideration. The framework is examined using the IEEE 33-bus and IEEE 69-bus systems under various operation scenarios. Besides the base case analysis, both line outage and line input are considered at different positions in the DN. Simulation results reveal the extended smart applicability of the framework, as well as, more efficient functionality over the traditional approaches for improving the smart grid performance via DN reconfiguration considering both soft and hard constraints. The simulation results figure out that the power losses ( ) can be minimized by 58.81%, and the minimum voltage magnitude ( ) can be improved by 7.25%, for the 33-bus system. For the 69-bus system, the reduction ratio of is 64.70%, and improvement is 4.48%.