Tools are becoming available for implementing systems with CoAP.
Access CoAP nodes via HTTP, analyze pcaps (tcpdump/wireshark packet capture files) and run the ETSI interoperability tests against your server on this simple interactive website.
Additional resources are available at vs0.inf.ethz.ch including DTLS support.
A protocol dissector for CoAP has been part of Wireshark for quite some time, supporting the development of CoAP. The final CoAP protocol is supported by Wireshark 1.12, the stable version of Wireshark.
A CoAP server which translates incoming CoAP requests to corresponding HTTP requests which are sent to a backend HTTP server; responses are translated to CoAP and sent over to the CoAP client. crosscoap allows CoAP clients to consume content from an existing HTTP application, without adding specific CoAP functionality to the application itself.
A number of interoperability tests have been defined by the ETSI plugtest organization. Californium contains support for this test suite. Access tester implementations via coap.me and read more details at:
ETSI is also periodically running interoperability testing events (“plugtests”). A next date for one has not yet been set; to keep up to date send mail to the ETSI plugtests people.
Zach Shelby has made available a CoAP overview and tutorial. Slides here; watch at:
A cheatsheet summarizing the frame structure, the option structure and the most important constants of CoAP is available at:
ABNF rules that are relevant to the formats around CoAP (link-format, URI syntax) is being collected at: