IoT protocols [List] behind the next technological revolution

What are the IoT protocols that are at the base of the Internet of things?

Before answering this question, it is useful to have an overview about IoT.

Internet of things is gaining appeal and the most important players are investing in IoT. Internet of things promises to be a technological revolution that will invest every area: industrial, transportation, energy everyday life and so on. As we have seen in previous posts there are several IoT definitions highlighting different aspects and there are many solutions to implement IoT projects.

IoT promises to connect all the devices together and enable them to exchange information like wearable, home devices, smart objects. All this information is gathered and analyzed to improve our life. If you are new to internet of thing, you should read before going on, what is Iot and how it will impact our everyday life and work.

But how these devices send and receive data? We all know HTTP protocol that makes possible to browse the net, opens web pages and so on. Is this protocol still useful for IoT?

Well, the answer is yes but there are other IoT protocols that can be more efficient and suitable for low power devices. Before reading this article you should read how to use 6 IoT prototyping boards that make Internet of things easier.

iot protocols

IoT protocols

Below, you will find a list of the most “important” IoT protocols used in IoT ecosystem:

  • MQTT
  • COAP
  • AMQP
  • Rest
  • XMPP
  • Stomp
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MQTT stands for Message Queuing Telemetry Trasport. MQTT is a publish/subscribe message lightweight protocol. MQTT is a M2M (Machine to Machine) oriented protocol. Now it is an open standard maintained by OASIS group. The reference architecture is very simple and it is based on client/server. The client is generally a sensor that “publish” the information to the server (broker) that receives the information and dispatch it to the subscribers. The underlying communication is based on TCP.

mqtt model

Generally speaking, MQTT protocol uses a many-to-many paradigm and the broker decouples the publisher to the subscriber and acts as a message router. This protocol implements QoS, secure communication, persistence and so on.  There is another version of this MQTT IoT protocol called MQTT-SN (or MQTT-S) that stand for Sensor network. Eclipse has released an open source implementation of MQTT called Mosquitto. Maybe MQTT is the most known IoT protocols among other IoT protocols.

MQTT is one of the most important protocols in IoT. How to install it and use it? Find more at MQTT Protocol Tutorial.


COAP stands for Constrained Application Protocol. This protocol was designed by IETF. It is a M2M protocol, defined by RFC7252, and it is web transfer protocol. This protocol is very similar to HTTP and it uses the document transfer paradigm. Moreover, It uses request/response model and supports built-in service discovery. Respect to HTTP protocol, COAP is lightweight with smaller packets.

COAP uses UDP as the underlying network protocol. COAP is basically a client-server IoT protocol where the client makes a request and the server sends back a response as it happens in HTTP. The methods used by COAP are the same used by HTTP.

MQTT, CoAP AMQP are IoT protocols that powers Internet of thingClick To Tweet


AMQP stands for Advanced Message Queue Protocol. It is maintained by OASIS as MQTT. AMQP is an open standard to exchange messages between applications (M2M). In other words, it is a message-oriented protocol that provides features like routing and queuing. The key factors of AMQP are:

  • open
  • interoperable
  • secure
  • reliable


We all know Rest protocol. Rest stands for (Representational state transfer). This protocol, used as IoT protocol, is exploited to exchange data between applications and to integrate applications belonging to different domains. Moreover, it uses HTTP as based protocol. Rest uses client/server paradigm. Rest is widely used not only in IoT ecosystem. We discussed how to use Rest to integrate Arduino with Android. Recently, Google has released a new OS based on Android to simplify the process of developing IoT app. It is very easy to expose a Rest API in Android Things and integrate it with external systems like apps.


XMPP (Extensible Messaging and Presence Protocol) is an open standard for presence and messaging. This protocol uses XML messages The XMPP-IoT is designed specifically for IoT environment. Basically, this protocol enables users to send real-time messages and handles the user presence (Online, Offline, Busy). The IoT version enables users to send and receive messages from machines. Moreover,  it is eXtensbile easily. The key factors are:

  • Extensible
  • Open standard
  • Flexible


Stomp is a text-oriented messaging protocol. It is very easy to use. Clients connect to a message broker to exchange messages.

At the end, finally,  you gained an overview of IoT protocols and what are their key points. As you have seen in this IoT protocol List there are some protocols we have used and we still use in different scenarios while some IoT protocols are IoT specific.

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