Choice of effective messaging protocols for IoT systems: MQTT, CoAP, AMQP and HTTP

TLDR

Real‑time communication is essential for IoT applications, yet no single protocol satisfies all messaging needs, making protocol selection a critical challenge. This study evaluates the four widely used protocols—MQTT, CoAP, AMQP, and HTTP—to guide IoT system designers in choosing the most suitable messaging solution. The authors first compare the protocols’ core characteristics, then conduct a detailed, criteria‑based analysis to reveal each protocol’s strengths and limitations. The resulting assessment enables users to match protocol choice to specific IoT system requirements and suitability.

Abstract

The standard and real-time communication technology is an unalloyed inevitability for the development of Internet of Things (IoT) applications. However, the selection of a standard and effective messaging protocol is a challenging and daunting task for any organisation because it depends on the nature of the IoT system and its messaging requirements. Copious messaging protocols have been developed and employed by various organisations based on their requirements in the last two decades. Though, none of them is able to support all messaging requirements of all types of IoT systems. Messaging protocol is an ongoing dilemma for the IoT industry; consequently, it is important to understand the pros and cons of the widely accepted and emerging messaging protocols for IoT systems to determine their best-fit scenarios. Therefore, this paper presents an evaluation of the four established messaging protocols MQTT, CoAP, AMQP and HTTP for IoT systems. Firstly, it presents the broad comparison among these messaging protocols to introduce their characteristics comparatively. Afterwards, it performs a further in-depth and relative analysis based on some interrelated criteria to gain insight into their strengths and limitations. Thus, based on this detailed evaluation, the user can decide their appropriate usage in various IoT systems according to their requirements and suitability.