The Constrained Application Protocol, or CoAP, is a specialized internet protocol designed for use in low-power and resource-constrained devices, such as those found in the Internet of Things (IoT). It enables these devices to communicate efficiently over networks, allowing for simple request and response interactions similar to HTTP but optimized for smaller data packets. CoAP operates over UDP (User Datagram Protocol), which helps reduce overhead and improve speed. It supports features like multicast requests and built-in reliability mechanisms, making it suitable for applications in smart homes, industrial automation, and environmental monitoring, where devices often have limited processing power and memory.