System Design Series: Apache Flink from 10,000 Feet, and Building a Flink-powered Recommendation Engine

Apache Flink is a distributed stream processing framework designed to handle high-scale, continuous data in real time. It resolves the long-standing tension between batch and streaming systems by treating batch processing as a special case of streaming where the data stream has a defined end. This unified approach eliminates the need for separate codebases and reduces latency, which is critical for applications like fraud detection and live analytics. The framework's utility is demonstrated by building a Flink-powered recommendation engine that processes user clicks and views as they happen to provide immediate, relevant suggestions.