This document provides an overview of Cloudera Manager APIs and extensibility. It discusses how the Cloudera Manager API, introduced in version 4.0, allows programmatic access to cluster operations and monitoring information. It provides examples of integration with the API for installation/deployment and monitoring/alerting. It also covers the tsquery language for custom metrics and monitoring, and new capabilities in Cloudera Manager 5 for user-defined triggers/alarms and service extensibility.