RFC 7252: The Constrained Application Protocol (CoAP)
In plain English — editorial summary, not part of the RFC
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.
Document record
- Document ID
- RFC7252
- Published
- June 2014
- Authors
- Z. Shelby; K. Hartke; C. Bormann
- Status
- PROPOSED STANDARD
- Stream
- IETF
- Area
- wit
- Pages
- 112
- Also known as
- —
Referenced by
5 later RFCs formally update or obsolete part of this document.
- RFC 7959Block-Wise Transfers in the Constrained Application Protocol (CoAP)Updated
August 2016
- RFC 8613Object Security for Constrained RESTful Environments (OSCORE)Current
July 2019
- RFC 8974Extended Tokens and Stateless Clients in the Constrained Application Protocol (CoAP)Current
January 2021
- RFC 9175Constrained Application Protocol (CoAP): Echo, Request-Tag, and Token ProcessingCurrent
February 2022
- RFC 9876Updates to the IANA Registration Procedures for Constrained Application Protocol (CoAP) Content-FormatsCurrent
November 2025
Related documents
Ranked automatically by shared keywords, IETF area and stream — not by editorial selection.
- RFC 7237Initial Hypertext Transfer Protocol (HTTP) Method RegistrationsCurrent
June 2014
- RFC 7236Initial Hypertext Transfer Protocol (HTTP) Authentication Scheme RegistrationsCurrent
June 2014
- RFC 7235Hypertext Transfer Protocol (HTTP/1.1): AuthenticationObsoleted
June 2014
- RFC 7234Hypertext Transfer Protocol (HTTP/1.1): CachingObsoleted
June 2014
- RFC 7233Hypertext Transfer Protocol (HTTP/1.1): Range RequestsObsoleted
June 2014
- RFC 7232Hypertext Transfer Protocol (HTTP/1.1): Conditional RequestsObsoleted
June 2014
- RFC 7272Inter-Destination Media Synchronization (IDMS) Using the RTP Control Protocol (RTCP)Current
June 2014
- RFC 7231Hypertext Transfer Protocol (HTTP/1.1): Semantics and ContentObsoleted
June 2014
Also filed under
About this page
The document record above — title, authors, date, status, stream, area, relationships, DOI and errata — is imported verbatim from the public RFC Editor index. The “in plain English” section is editorial: written by The metasystema editorial team, not part of the RFC. Where the two differ, the RFC text governs.
Last checked against the RFC Editor index on . RFCs are never revised after publication; changes are issued as new documents.
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