More and more data sources today provide a constant stream of data, from IoT devices to Social Media streams. It is one thing to collect these events in the velocity they arrive, without losing any single message. An Event Hub and a data flow engine can help here. It’s another thing to do some (complex) analytics on the data. There is always the option to first store in a data sink of choice and later analyze it. Storing even a high-volume event stream is feasible and not a challenge anymore. But this adds to the end-to-end latency and it takes minutes if not hours to present results. If you need to react fast, you simply can’t afford to first store the data. You need to do process it directly on the data stream. This is called Stream Processing or Stream Analytics. In this talk I will present the important concepts, a Stream Processing solution should support and then dive into some of the most popular frameworks available on the market and how they compare.