Where is mqtt used

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Last updated: April 8, 2026

Quick Answer: MQTT (Message Queuing Telemetry Transport) is a lightweight publish-subscribe network protocol designed for constrained devices and low-bandwidth networks, first standardized by OASIS in 2014. It's widely used in IoT applications, with over 1.5 billion devices expected to use MQTT by 2025, particularly in industrial automation, smart home systems, and automotive telematics.

Key Facts

MQTT was created in 1999 by Andy Stanford-Clark and Arlen Nipper for oil pipeline monitoring
Standardized by OASIS in 2014 (MQTT v3.1.1) and ISO/IEC in 2016
Uses TCP/IP port 1883 (unencrypted) or 8883 (TLS encrypted)
Supports three Quality of Service levels: 0 (at most once), 1 (at least once), and 2 (exactly once)
Facebook Messenger used MQTT for its chat system until 2018, handling billions of messages daily

Overview

MQTT (Message Queuing Telemetry Transport) is a lightweight, publish-subscribe messaging protocol designed specifically for constrained devices and low-bandwidth, high-latency networks. Originally developed in 1999 by Andy Stanford-Clark of IBM and Arlen Nipper of Arcom (now Eurotech), it was created to monitor oil pipelines via satellite connections where bandwidth was expensive and unreliable. The protocol's design prioritizes minimal network bandwidth and device resource requirements while ensuring reliable message delivery.

The protocol gained significant traction with the rise of the Internet of Things (IoT) due to its efficiency and simplicity. In 2014, MQTT version 3.1.1 was standardized by OASIS, and in 2016 it became an ISO/IEC standard (ISO/IEC 20922). Today, MQTT is maintained by the Eclipse Foundation through the Eclipse Mosquitto project and has become one of the most widely adopted protocols for machine-to-machine (M2M) communication.

How It Works

MQTT operates on a publish-subscribe architecture with three main components: publishers, subscribers, and a broker.

Key Point 1: Publish-Subscribe Architecture: Unlike traditional client-server models, MQTT uses a topic-based system where devices publish messages to topics and subscribe to topics they're interested in. A single MQTT broker can handle thousands of concurrent connections, with typical implementations supporting 50,000+ simultaneous connections on modest hardware. Messages are typically small, often under 256 bytes, making them ideal for constrained networks.
Key Point 2: Quality of Service Levels: MQTT provides three QoS levels to balance reliability and performance. QoS 0 (at most once) provides fire-and-forget delivery with no acknowledgment. QoS 1 (at least once) ensures delivery but may result in duplicates. QoS 2 (exactly once) guarantees exactly one delivery through a four-step handshake process. Most IoT applications use QoS 1 as it provides reliable delivery without the overhead of QoS 2.
Key Point 3: Connection Management: MQTT uses a persistent TCP connection (port 1883 for unencrypted, 8883 for TLS) that remains open as long as the client is active. The protocol includes a "Last Will and Testament" feature that allows clients to specify a message to be published if they disconnect unexpectedly. Keep-alive intervals (typically 60 seconds) ensure connections remain active even during periods of inactivity.
Key Point 4: Security Features: While the base protocol doesn't include built-in security, MQTT commonly implements TLS/SSL encryption for data in transit. Authentication can be handled via username/password credentials or client certificates. Modern implementations often integrate with OAuth 2.0 and other authentication protocols for enterprise deployments.

Key Comparisons

Feature	MQTT	HTTP
Protocol Overhead	2-byte fixed header + variable payload	100+ bytes typical header
Connection Model	Persistent TCP connection	Request-response (stateless)
Message Size	Optimized for small messages (<256B typical)	Designed for larger payloads
Power Consumption	Low (efficient for battery devices)	Higher (frequent connection setup)
Real-time Capability	Excellent (push-based delivery)	Poor (requires polling)

Why It Matters

Impact 1: IoT Scalability: MQTT enables massive IoT deployments by minimizing bandwidth usage and server load. A single MQTT broker can handle millions of messages per second, with cloud providers like AWS IoT Core and Azure IoT Hub reporting support for billions of devices. This scalability has been crucial for smart city deployments where thousands of sensors need to communicate efficiently.
Impact 2: Industry Transformation: In manufacturing, MQTT has enabled Industry 4.0 by allowing real-time monitoring of production lines. Siemens reports that their MQTT-based Industrial Edge systems have reduced downtime by up to 30% in factory automation. The protocol's reliability ensures critical alerts about equipment failures reach operators within milliseconds.
Impact 3: Energy Efficiency: MQTT's lightweight nature makes it ideal for battery-powered devices. Compared to HTTP, MQTT can reduce energy consumption by up to 90% for periodic sensor reporting. This has enabled long-lasting environmental monitoring stations and wearable health devices that can operate for years on small batteries.

Looking forward, MQTT 5.0 (released in 2019) introduces enhanced features like message expiration, shared subscriptions, and improved error reporting that will further expand its applications. As edge computing grows and 5G networks enable more connected devices, MQTT's efficient design positions it as a foundational protocol for the next generation of connected systems. The protocol continues to evolve with emerging standards like MQTT-SN for sensor networks and increasing integration with cloud-native architectures.