The Internet of Things is getting momentum and generating new demands over infrastructure, systems, and platforms. One of the main aspects that hamper the large-scale development of IoT-based systems is the lack of interoperability. IoT Platforms aim to solve this issue by providing a uniform interface to access data from heterogeneous sources. However, integrating new protocols and applications can impose additional overhead, hindering the platform’s overall performance and scalability. This study provides an insight into the trade-off between interoperability and performance of IoT platforms. First, we present a qualitative analysis of three open-source platforms - FIWARE, ThingsBoard, and Konker - analyzing their interoperability features. Second, we conduct a performance evaluation emulating two IoT-based environments – smart cities and smart health – to understand each platform’s scalability, response time, and computer resource usage. Finally, we analyze the possible trade-offs between interoperability features and scalability based on the qualitative and quantitative analysis. The results show that interoperability features do not have a direct impact on the performance of the platform.