NATS is a high-performance messaging system designed for cloud-native applications, IoT messaging, and microservices architectures. It provides a lightweight, open-source communications platform that supports multi-cloud, on-premises, and hybrid cloud deployments. NATS is known for its simplicity, low latency, and scalability, making it a popular choice for distributed systems needing reliable and real-time messaging solutions. It supports various messaging patterns, such as publish/subscribe, request/reply, and distributed queueing.