Nowadays, analytics are at the core of many emerging applications and can greatly benefit from the abundance of data and the progress in the processing capabilities of modern hardware. Still, new challenges arise with the extreme complexity of designing applications to exploit in full the potential of such offerings. In this work, we describe the main challenges in delivering advanced, cross-platform, streaming analytics at scale with the primary goal of interactivity. We present the architecture of a prototype system designed from scratch to tackle such challenges and we describe the internals of its components. Finally, we discuss key added-value synergies upon serving target analytics workflows in real-world applications and present a preliminary performance evaluation.