Apache Flink

Apache Flink is an open source stream processing framework maintained by the Apache Software Foundation, specializing in high-performance stateful computations over data streams. Flink supports exactly-once semantics, ensuring data processing is neither lost nor duplicated, making it the preferred framework for building reliable streaming applications. The framework supports both stream and batch processing, treating batch as a special case of streaming, providing a unified data processing API. Flink features event-time processing capabilities that correctly handle out-of-order data arrivals, supporting windowing operations, state management, and checkpoint mechanisms to ensure accuracy and consistency during failures. Flink provides DataStream API and Table API plus SQL as programming interfaces, supporting Java, Scala, and Python. The framework includes rich built-in connectors for seamless integration with Kafka, Kinesis, Elasticsearch, JDBC, and other data sources. Flink is widely used at major internet companies including Alibaba, Uber, and Netflix for real-time data analytics, online machine learning, complex event processing, and ETL pipelines. As a next-generation stream processing engine, Apache Flink has established itself as the technology benchmark in real-time data processing through its low latency, high throughput, and powerful state management capabilities that set industry standards.