Apache Spark is an open-source cluster computing framework for real-time processing. It is of the most successful projects in the Apache Software Foundation. Spark has clearly evolved as the market leader for Big Data processing. It provides high-level APIs in Java, Scala, Python and R, and an optimized engine that supports general execution graphs. It also supports a rich set of higher-level tools including Spark SQL for SQL and structured data processing, MLlib for machine learning, GraphX for graph processing, and Spark Streaming.
For more info, please check the Apache Spark Documentation.