SynapseML is an open-source library that simplifies the creation of massively scalable ML pipelines. Built on Apache Spark and sharing the same API as SparkML/MLLib, it provides simple and composable distributed APIs for tasks including deep learning, text analytics, computer vision, and anomaly detection. The library supports training and evaluating models across single-node, multi-node, and elastically resizable clusters, with support for Python, R, Scala, Java, and .NET.