In this paper, we introduce an integrated smart parking system. The proposed integrated smart parking system brings multiple parking service providers together under a unified platform aiming to provide one-stop parking information services to the commuters in a smart city. However, the adaptation of such a system is prone to tempering while a massive amount of data is shared among different parties which raise concerns related to trust and performance. To address this challenge, we propose a blockchain-based architecture specific to the integrated smart parking systems. Finally, we present a set of design principles which shows the applicability of our proposed blockchain-based integrated parking system.