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MQTT client/server for C++14 based on Boost.Asio

Version 13.2.1 Actions StatusBuild Statuscodecov

mqtt_cpp has been serious bugfix only status. The new project async_mqtt has been started based on mqtt_cpp's experience. New featureas would be added on async_mqtt.

MQTT v5 is supported since version 4.0.0.


mqtt_cpp is a header only library. It requires C++14 and the Boost Libraries 1.74.0 or later.

Add mqtt_cpp/include to your include path. Then, include mqtt_client_cpp.hpp and/or mqtt_server_cpp.hpp as follows:

For clients:

#include <mqtt_client_cpp.hpp>
#include <mqtt/setup_log.hpp> // if you want to use typical logging setup

For servers:

#include <mqtt_server_cpp.hpp>
#include <mqtt/setup_log.hpp> // if you want to use typical logging setup

You can compile your code as follows:

g++ -std=c++14 -Ipath_to_mqtt_cpp/include your_program.cpp -pthread additional_options

mqtt_cpp uses std::variant or boost::variant internally. If you define the preprocessor macro MQTT_STD_VARIANT then std::variant is chosen, otherwise boost::variant is chosen.

If you use boost::variant, you need to include mqtt/config.hpp prior to the boost headers inclusion becausse it defines boost configuration macros. When you use mqtt_client_cpp.hpp and/or mqtt_server_cpp.hpp, they include mqtt/config.hpp internally.

Experimental feature

In include/mqtt/broker, there are header files to implement mqtt broker. It is an experimental feature. It would frequently updated. Even if the broker interface would be changed, major version won't be updated.


what you want required option
TLS support -DMQTT_USE_TLS -pthread -lssl -lcrypto
Logging support -DMQTT_USE_LOG -DBOOST_LOG_DYN_LINK -lboost_log -lboost_filesystem -lboost_thread
WebSocket support -DMQTT_USE_WS

You can see more detail at


Usage in cmake project

Add following lines to your CMakeLists.txt

set(LIBNAME "your_project_name")
add_library(${LIBNAME} <your dependencies here>)

find_package(mqtt_cpp_iface REQUIRED)
target_link_libraries(${LIBNAME} LINK_PUBLIC mqtt_cpp_iface::mqtt_cpp_iface)

This uses the mqtt_cpp_iface::mqtt_cpp_iface target and includes all necessary link dependencies.


You can build tests and examples as follows:

At mqtt_cpp directory

mkdir build
cd build
cmake ..
make test


You can create html documents using doxygen.

make doxygen


mqtt_cpp is licensed under the Boost Software License, Version 1.0. See the LICENSE_1_0.txt file for details.