Smart emergency response systems, smart transportation systems, smart parking spaces are some examples of multi-domain smart city systems that require large-scale, open platforms for integration and execution. These platforms illustrate high degree of heterogeneity. In this paper, we focus on software heterogeneity arising from different types of applications. The source of variability among applications stems from (a) timing requirements, (b) rate and volume of data they interact with, and (c) behavior depending on whether they are stateful or stateless.