What is CoAP?

Constrained Application Protocol (CoAP), as its name implies, is tailored to run in constrained devices, such as microcontrollers.

Let’s see some characteristics:

• It runs on UDP.
• It has low header overhead and parsing complexity.
• Its packets are much smaller than HTTP.
• It has asynchronous message exchanges.
• It allows UPD broadcast and multicast.
• It has UIR and content-type support.
• It uses methods like HTTP: GET, PUT, POST, and DELETE.
• CoAP can interact with HTTP using proxies.
• It has low resource and power consumption.

Although CoAP uses UDP, it allows requesting confirmation packets. Any request or response message can be tagged as confirmable or nonconfirmable. If the receiver gets a message tagged as confirmable, it will send an ack to the sender. On the other hand, if the message is tagged as nonconfirmable, it will not send any ACK message. CoAP packets are transported over UDP, so you can’t use SSL...