Gaining insight in the properties of an Internet of Things (IoT) system during the design phase is difficult. The cosimulation of such a system would be very useful, but creating it is usually time consuming. By means of domain specific languages (DSLs) we support the fast construction of large co-simulations of IoT systems. This approach includes the use of CoHLA, a DSL that generates co-simulation code based on the HLA and FMI standards. Due to the large number of connected sensors and actuators in an IoT system, the time needed for simulation can be a blocking factor. Hence we facilitate distributed co-simulation in the cloud. To do that efficiently, we have conducted a set of experiments to analyse scalability and the performance impact of distribution methods. From these experiments, lessons were learned on how to distribute the co-simulation of IoT systems. © 2018 IEEE.