Apache Beam is an open-source unified model for defining both batch and streaming data processing pipelines. It allows developers to write their data processing logic once and run it on various execution engines, such as Apache Flink, Apache Spark, or Google Cloud Dataflow. This flexibility makes it easier to handle large-scale data processing tasks across different environments. The core concept of Apache Beam revolves around the use of PCollections, which represent collections of data, and Transforms, which are operations applied to these collections. By using a simple and consistent programming model, Apache Beam enables users to build complex data workflows efficiently, regardless of the underlying infrastructure.