MQTTnet is a high performance .NET library for MQTT based communication. It provides a MQTT client and a MQTT server (broker). The implementation is based on the documentation from http://mqtt.org/.

HiveMQ CE is a Java-based open source MQTT broker that fully supports MQTT 3.x and MQTT 5. It is the foundation of the HiveMQ Enterprise Connectivity and Messaging Platform

HiveMQ MQTT Client is an MQTT 5.0 and MQTT 3.1.1 compatible and feature-rich high-performance Java client library with different API flavours and backpressure support

A Lightweight and fully asynchronous MQTT client C library based on libev

Gmqtt is a flexible, high-performance MQTT broker library that fully implements the MQTT protocol V3.1.1 in golang

reactor3实现的mqtt库

MQTT broker written in D, using vibe.d

luamqtt - Pure-lua MQTT v3.1.1 and v5.0 client

General purpose library for communication over the mqtt protocol

Diagnostic-oriented MQTT client tool. Supports MQTT 5.0 and 3.1.X protocols, connections to multiple brokers, MQTT operations logs and multiple subscribe widgets with unique/history topic filtering mode. Saves configuration in browser's local cache.

Whsnbg is a C implementation of a MQTT server (broker), a MQTT-SN gateway and simple MQTT rules engine designed for embedded platforms with small memory requirements.

Implementation of MQTT protocol versions 3.1 and 3.1.1

MQTT broker in Rust

Async Mqtt encoder and decoder for rust.

An example Android app using MQTT protocol

IDE for IoT & friends

Kotlin cross-platform, coroutine based, reflectionless MQTT 3.1.1 & 5.0 client & server

Erlang/Elixir low level MQTT protocol implementation

MQTT Input Plugin for Graylog

Open source Extension SDK for the HiveMQ Enterprise MQTT broker that you can use to extend the broker with custom functionality and integrate the broker with other external systems

MQTT Demonstration and client using Android App

flespi-io-js is a library for connecting to flespi.io via http and mqtt protocols.

A no_std mqtt encoder/decoder in pure Rust for use in embedded systems.

Arduino Home Automation Arduino. Interface Arduino Nano with ENC28J60 ethernet module to communicate over internet via MQTT protocol.

A cli application written in Go to provide terminal interaction with EMQ

MQTT5 implementation by golang

AWS IOT development support on Windows

A highly scalable framework for the performance and energy monitoring of HPC servers

Contro an led-strip with an esp8266 from Home-Assistant via MQTT

Domoticz plugin for the EMS Wi-Fi Gateway with Proddy's EMS-ESP firmware