wolfMQTT Client Library

MQTT (Message Queuing Telemetry Transport) is a lightweight open messaging protocol that was developed for constrained environments such as M2M (Machine to Machine) and IoT (Internet of Things), where a small code footprint is required. MQTT is based on the Pub/Sub messaging principle of publishing messages and subscribing to topics. The protocol efficiently packs messages to minimize overhead. The MQTT specification recommends TLS as a transport option to secure the protocol using port 8883 (secure-mqtt), as the MQTT protocol does not provide security on its own. Constrained devices can benefit from using TLS session resumption to reduce the reconnection cost.

The wolfMQTT library is a client implementation of the MQTT written in C for embedded use. It supports SSL/TLS via the wolfSSL library. From this, it can provide the security that the MQTT protocol lacks. wolfMQTT was built from the ground up to be multi-platform, space conscious and extensible. It supports all Packet Types, all Quality of Service (QoS) levels 0-2 and supports SSL/TLS using the wolfSSL library. This implementation provides support for MQTT v5.0 and MQTT v3.1.1. Additionally, there is also client support for MQTT-SN (Sensor Network).

wolfMQTT is built for maximum portability, and is generally very easy to compile on new platforms. If your desired platform is not listed under the supported operating environments, please contact wolfSSL at facts@wolfssl.com.

Platform and Language Support

wolfMQTT is built for maximum portability and is generally very easy to compile on new platforms. If your desired platform is not listed under the supported operating environments, please contact us.

wolfMQTT supports the C programming language as a primary interface. If you have interest in using wolfMQTT in another programming language that it does not currently supported, please contact us.

Commercial Support

Support packages for wolfMQTT are available on an annual basis directly from wolfSSL. With three different package options, you can compare them side-by-side and choose the package that best fits your specific needs. Please see our Support Packages page for more details or contact us with any questions.

wolfSSL Training Course

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Features

Built from scratch by wolfSSL engineers
Supports MQTT specifications v3.1.1 and v5.0
Support for MQTT-SN
Supports all client side packet types and protocol options
QoS Levels 0-2 (guaranteed delivery)
Message integrity, security are still available
Supports plain TCP or TLS (via the wolfSSL library)
Single threaded model and single message callback
Written in Native C89 with portability/compatibility in mind
Space conscience design (Compiled size is about 3.6kB)
User manual with build instructions, example overview, and API documentation
Example MQTT client implementations
Network interface is abstracted via callbacks for extensibility
Packet parsing encoding/decoding structured for custom use
Minimal external dependencies (strlen, memcpy, memset)
Detailed error checking/handling
Doxygen style inline documentation
Less than 1200 lines of well structured C code
Tested on multiple variants of MQTT broker servers, QoS levels 0-2 with/without TLS
Tested on Linux, Mac OS X, and Freescale Kinetis K64
Inherits wolfSSL library features such as lightweight TLS using ChaCha20/Poly1305 AEAD, small size and portability
Open source (GPLv2)
FreeRTOS+TCP support
Example Arduino IDE project
IBM Watson IoT Example with IBM developer recipe
IBM Watson IoT Platform is a supported cloud provider
Example UART interface for wolfMQTT

Supported Operating Environments

Win32/64, Linux, Mac OS X, Solaris, ThreadX, VxWorks, FreeBSD, NetBSD, OpenBSD, embedded Linux, Yocto Linux, OpenEmbedded, WinCE, Haiku, OpenWRT, iPhone (iOS), Android, Nintendo Wii and Gamecube through DevKitPro, QNX, MontaVista, NonStop, TRON/ITRON/µITRON, Cesium, Micrium µC/OS-III, FreeRTOS, SafeRTOS, NXP/Freescale MQX, Nucleus, TinyOS, HP/UX, AIX, ARC MQX, TI-RTOS, uTasker, embOS, INtime, Mbed, uT-Kernel, RIOT, CMSIS-RTOS, FROSTED, Green Hills INTEGRITY, Keil RTX, TOPPERS, PetaLinux, Apache Mynewt, PikeOS
If you would like to test wolfSSL on another environment, let us know and we’ll be happy to support you.

PRODUCTS

Highlights

Lightweight

Portable