Cloud monitoring and observability platform. APM, logs, metrics, security, real-user monitoring; the most-installed observability SaaS.
From Wikipedia
Datadog, Inc. is an American company that provides an observability service for cloud-scale applications, providing monitoring of servers, databases, tools, and services, through a SaaS-based data analytics platform. Founded and headquartered in New York City, the company is a publicly traded entity on the Nasdaq stock exchange.