Due to the growing need to timely process and derive valuable information and knowledge from data produced in the Semantic Web, RDF stream processing (RSP) has emerged as an important research domain. In this paper, we describe the design of an RSP engine that is built upon state of the art Big Data frameworks, namely Apache Kafka and Apache Spark. Together, they support the implementation of a production-ready RSP engine that guarantees scalability, fault-tolerance, high availability, low latency and high throughput. Moreover, we highlight that the Spark framework considerably eases the implementation of complex applications requiring libraries as diverse as machine learning, graph processing, query processing and stream processing.