**Co**nstrained **A**pplication **P**rotocol A specialized web transfer protocol for use with constrained nodes (small amount of ROM and RAM) and constrained (e.g., low-power, lossy) networks. The protocol is designed for machine-to-machine (M2M) applications such as smart energy and building automation. ## Sources https://datatracker.ietf.org/doc/html/rfc7252