Datadog is a full monitoring platform; it supports various servers, platforms, and applications. Wikipedia describes the service as:
"Datadog is a SaaS-based monitoring and analytics platform for IT infrastructure, operations and development teams. It brings together data from servers, databases, applications, tools and services to present a unified view of the applications that run at scale in the cloud."
It uses an agent that is installed on your host machine; this agent sends metrics back to the Datadog service periodically. It also support multiple cloud platforms, such as Amazon Web Services, Microsoft Azure, and OpenStack to name a few.
The aim is to bring all of your servers, applications, and host provider metrics into a single pane ...