CoAP

CoAP is another IoT messaging protocol, UDP-based and intended for use in resource-constrained internet devices such as wireless sensor nodes. CoAP uses DTLS for security services. CoAP consists of a set of messages that map easily to HTTP: GET, POST, PUT, and DELETE:

CoAP device implementations communicate to web servers using specific Uniform Resource Indicators (URIs) to process commands. Examples of CoAP-enabled implementations include smart light switches in which the switch sends a command to change the behavior (state/color) of each light in the system.