The Constrained Application Protocol (CoAP), June 2014
- File formats:
- PROPOSED STANDARD
- Updated by:
- RFC 7959, RFC 8613, RFC 8974, RFC 9175
- Z. Shelby
- core (app)
Discuss this RFC: Send questions or comments to the mailing list email@example.com
The Constrained Application Protocol (CoAP) is a specialized web transfer protocol for use with constrained nodes and constrained (e.g., low-power, lossy) networks. The nodes often have 8-bit microcontrollers with small amounts of ROM and RAM, while constrained networks such as IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs) often have high packet error rates and a typical throughput of 10s of kbit/s. The protocol is designed for machine- to-machine (M2M) applications such as smart energy and building automation.
CoAP provides a request/response interaction model between application endpoints, supports built-in discovery of services and resources, and includes key concepts of the Web such as URIs and Internet media types. CoAP is designed to easily interface with HTTP for integration with the Web while meeting specialized requirements such as multicast support, very low overhead, and simplicity for constrained environments.
For the definition of Status, see RFC 2026.
For the definition of Stream, see RFC 8729.