Astronomy:Comparison of MQTT implementations

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MQTT is an ISO standard (ISO/IEC PRF 20922)[1] publish–subscribe-based messaging protocol. It works on top of the Internet protocol suite TCP/IP. It is designed for connections with remote locations where a "small code footprint" is required or the network bandwidth is limited. The publish-subscribe messaging pattern requires a message broker.

All comparison categories use the stable version of each implementation listed in the overview section. The comparison is limited to features that relate to the MQTT protocol.

Overview

The following table lists MQTT both libraries and implementations, along with general information about each.

Implementation Developed by Open source Software license Copyright owner Programming language Type Latest stable release, release date Origin
Adafruit IO Adafruit Yes MIT Adafruit Ruby, Node.js, Python, Go[2] Client 2.0.0,[3]
?
US
Amlen[4] Eclipse Yes EPL 2.0 Eclipse Foundation C Broker 1.0.0.0 2022-05-25
Azure Event Grid MQTT broker Microsoft No Commercial Microsoft C, C#/.NET, Java, JavaScript (NodeJs), Python, Go Broker 2023-06-01-preview,[5]
2023-05-25
US
EMQX[6] EMQ Yes Apache License 2.0 EMQ Technologies Inc. Erlang[7] Broker V5.3.1,[8]
2023-11-14
China
EMQX Enterprise[9] EMQ No Commercial EMQ Technologies Inc. Erlang Broker v5.3.1,[10] 2023-11-14 China
LMQTT[11] Real Time Logic[12] Yes GPL or Commercial Real Time Logic Lua Client ?

2022-10-07

US
NanoMQ[13] EMQ Yes MIT EMQ Technologies Inc. C Broker and client 0.5.8 China
MQTT X[14] EMQ Yes Apache License 2.0 EMQ Technologies Inc. TypeScript Client v1.7.1 China
FairCom Edge[15] FairCom No Commercial FairCom Corporation C Broker 3.0.0, 2020-11-01[16] US
FlashMQ[17] Wiebe Cazemier Yes OSL3 Wiebe Cazemier C++ Broker 1.7.10, 2023-11-03 Netherlands
flespi[18] Gurtam No Commercial Gurtam C Broker 2018-04-05 Belarus
GridServer GRID System No Commercial GRID System S.A.S Pascal, Delphi Broker 2019-09-15 France
HiveMQ MQTT Client[19] HiveMQ Yes Apache License 2.0 HiveMQ Java Client 1.3.1,[20]
2023-04-12
Germany
HiveMQ Community Edition[21] HiveMQ Yes Apache License 2.0 HiveMQ Java Broker 2024.1,[22]
2024-01-09
Germany
HiveMQ[23] HiveMQ No Commercial HiveMQ Java Broker 4.24,[24]
2024-01-09
Germany
IBM WIoTP Message Gateway[25] IBM No Commercial IBM C Broker 5.0.0.1 2019-02-29
JoramMQ[26] ScalAgent D.T. No, based on OW2/Joram 5.19, open-source broker (LGPL) Commercial ScalAgent D.T. Java Broker 1.16 2022-06-07 France
KMQTT[27] Davide Pianca Yes MIT Davide Pianca Kotlin Broker 0.4.1,[28]

2023-04-12

Italy
LV-MQTT Francois Normandin Yes 0-BSD License G Open Source Project for LabVIEW LabVIEW Broker and client 3.2.0 Canada
M2Mqtt[29] Eclipse Yes Eclipse Public License 1.0 Eclipse C# Client 4.3.0.0,[30]
2017-05-20
Canada
Machine Head[31] ClojureWerkz[32] Yes Creative Commons Attribution 3.0 Unported License Alexander Petrov, Michael Klishin, ClojureWerkz Team Clojure Client 1.0.0,[31]
2017-03-05
Mongoose Library[33] Cesanta Yes GPLv2 or Commercial Cesanta C / C++ Client[34] and Broker[35] 7.9

2023-01-24

Ireland
moquette[36] Andrea Selva Yes Apache License 2.0 Andrea Selva Java Broker 0.16,[37]
2023-01-06
Italy
Mosquitto[38] Eclipse Yes Eclipse Public License 2.0, Eclipse Distribution License 1.0 (BSD) Eclipse C Client and broker 2.0.18,[39]
2023-09-18
UK
MQTT🤖[40] Pascal de Kloe Yes Public domain nobody Go Client v1.0.0, 2020-02-22 The Netherlands
MQTT-C[41] Liam Bindle Yes MIT Liam Bindle C Client 1.1.5,[42]
2021-04-01
Canada
mqttools[43] Erik Moqvist Yes MIT Erik Moqvist Python Client and broker 0.34.0, 2020-01-20 Sweden
net-mqtt[44] Dustin Sallings Yes BSD 3-Clause Dustin Sallings Haskell Client 0.6.0.0, 2019-10-12 US
OpenRemote MQTT Broker[45] OpenRemote Yes AGPLv3 OpenRemote Java Broker 3.0.1, 2021-03-10 US
Paho MQTT[46] Eclipse Yes Eclipse Public License 1.0, Eclipse Distribution License 1.0 (BSD)[47] Eclipse C, C++, C#, Go, Java, JavaScript, Python, Rust[48] Client 1.4.0 (Photon),[49]
2018-06-27
UK
PubSub+[50] Solace No Commercial, free version Solace C, C#/.NET, Java, JavaScript (NodeJs), Python, Go[51][52] Broker 9.8.1
2021-01-14[53]
Canada
RMQTT rmqtt Yes MIT rmqtt Rust Broker 0.2.20

2023-11-04

SharkMQTT[54] Real Time Logic[55] Yes GPL or Commercial SharkSSL C Client 4829

2021-10-04

US
Thingstream[56] Thingstream No Commercial Thingstream C, C++, Java, JavaScript, Python, Go Client and broker 3.3.0

2019-03-14[57]

UK
VerneMQ[58] VerneMQ/Octavo Labs Yes Apache License 2.0 VerneMQ/Octavo Labs Erlang/OTP Broker 1.13.0

2023-06-06

Switzerland
wolfMQTT[59] wolfSSL[60] Yes GNU General Public License, version 2, Commercial[59] wolfSSL C Client 1.11.0[61]
2022-01-07
US
eMQTT5[62] Cyril Russo Yes MIT Cyril Russo C++ Client 1.0, 2020-03-31 France
Bevywise MQTTBroker[63] Bevywise Networks No Commercial Bevywise Networks C, Python Broker v1.1, 2018-10-20 India
OpenHAB MQTT binding[64] OpenHAB Yes Eclipse Public OpenHAB Java Client 2.5.4, 2020-04-21 Germany
Waterstream[65] SimpleMatter[66] No Commercial SimpleMatter Srl Kotlin Broker 1.00.03 Italy
MQTTDESK MQTT Client[67] ioCtrl No Commercial ioCtrl Node.js Client v2.1.0, 2021-05-25 India
MQTTnet .NET Foundation Yes MIT .NET Foundation C# Client and broker v4.1.3.436 US

A more complete list of MQTT implementations can be found on GitHub.

Protocol support

There are several versions of the MQTT protocol currently standardized. Below is a list containing the more recent versions of the MQTT protocol, with the organization that standardized them.

The following table lists the versions of MQTT that each implementation supports, and also lists their support for SSL/TLS and TCP. The security provided by SSL/TLS may be desirable depending on the type traffic being sent between devices, as MQTT transmits messages in the clear.[73]

Implementation MQTT-SN v1.2 MQTT 3.1 MQTT 3.1.1 MQTT 5.0 SSL/TLS TCP WS/WSS
Amlen Yes Yes Yes Yes Yes Yes
Azure Event Grid MQTT broker Yes Yes[74] Yes Yes Yes
EMQX Yes Yes Yes Yes Yes Yes Yes
FairCom Edge Yes Yes Yes Yes[75] Yes Yes
FlashMQ Yes Yes Yes Yes Yes Yes
flespi Yes Yes Yes[76] Yes Yes Yes
HiveMQ Yes (only for broker) Yes Yes[77] Yes Yes Yes
IBM WIoTP Message Gateway Yes Yes Yes Yes Yes Yes
JoramMQ Yes Yes Yes Yes Yes Yes Yes
KMQTT Yes Yes Yes Yes Yes
LMQTT via old stack via old stack Yes Yes Yes Yes
LV-MQTT Yes Yes Yes Yes Yes
M2Mqtt Yes Yes Yes Yes
Machine Head
Mongoose Yes Yes Yes Yes Yes Yes
moquette Yes Yes Yes[78] Yes
Mosquitto Yes Yes Yes Supports certificate-based and pre-shared-key-based SSL/TLS,

general support for SSL/TLS across bridges[79]

Yes Yes
MQTT-C Yes Yes Yes Yes
mqttools Yes Yes Yes
net-mqtt Yes Yes Yes Yes Yes Yes
Paho MQTT[46] Yes[80] Yes Yes Yes (only in C and Java client library)[81] Yes Yes Yes
RMQTT Yes Yes Yes Yes Yes Yes
Solace PubSub+ Yes[82] Yes[83] Yes Yes Yes
SharkMQTT Yes Yes Yes Yes
Thingstream Yes Yes Yes Yes
VerneMQ Yes Yes Yes Yes Yes Yes
wolfMQTT Yes Yes Yes Yes Yes
eMQTT5 Yes Yes Yes
Bevywise Networks Yes Yes Yes Yes Yes Yes
Waterstream Yes Yes Yes Yes
MqttDesk Yes Yes Yes Yes Yes Yes
MQTTnet Yes Yes Yes Yes Yes Yes

Quality of service levels offered

Main page: Quality of service

From the MQTT page, quality of service (QoS) is described as,

Quality of service refers to traffic prioritization and resource reservation control mechanisms rather than the achieved service quality. Quality of service is the ability to provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow.

A description of each QoS level is found below.[84]

  1. At most once delivery (fire and forget)
  2. At least once delivery (acknowledged delivery)
  3. Exactly once delivery (assured delivery)

The following table lists each implementation's support of the QoS levels.

Implementation 0 1 2
Adafruit IO Yes Yes No[85]
Amlen[86] Yes Yes Yes
Azure Event Grid MQTT broker[87] Yes Yes No
EMQX[88] Yes Yes Yes
FairCom Edge Yes Yes Yes
FlashMQ Yes Yes Yes
flespi[76] Yes Yes Yes
HiveMQ[89] Yes Yes Yes
IBM WIoTP Message Gateway Yes Yes Yes
JoramMQ Yes Yes Yes
KMQTT Yes Yes Yes
LMQTT Yes Yes Yes
LV-MQTT Yes Yes Yes
M2Mqtt[29] Yes Yes Yes
Mongoose Yes Yes Yes
moquette[90] Yes Yes Yes
Mosquitto[91] Yes Yes Yes
MQTT-C Yes Yes Yes
mqttools Yes No No
net-mqtt Yes Yes Yes
Paho MQTT Yes Yes Yes
Solace PubSub+ Yes Yes No[92]
SharkMQTT Yes Yes Yes
Thingstream Yes Yes Yes
VerneMQ Yes Yes Yes
wolfMQTT[59] Yes Yes Yes
eMQTT5 Yes Yes Yes
Bevywise MQTTBroker Yes Yes Yes
Waterstream Yes Yes Yes
MqttDesk MQTT Client Yes Yes Yes
MQTTnet Yes Yes Yes

Portability concerns

Portability concerns in this section refers to technical details that may be deciding factors in selecting an implementation to use. In general, this table should be used by those with more knowledge about the device they will be using.

Implementation Platform requirements Network requirements Thread safety Able to cross-compile Bare metal
Adafruit IO Adafruit Feather Huzzah, ESP8266, Raspberry Pi, Arduino, any platform that supports Python, Ruby, or Node.js Platform-dependent
Amlen Linux Yes Yes
EMQX Linux, Unix, macOS, Windows, Raspberry Pi[93] Yes Yes Yes
Faircom Edge Linux, MacOS, Windows, Raspberry Pi, Android Yes Yes Yes
flespi
HiveMQ JVM, Linux, macOS, Windows, Raspberry Pi Yes Yes Yes
JoramMQ JVM, Linux, macOS, Windows, Raspberry Pi Yes Yes Yes
KMQTT JVM, Linux, Windows, Raspberry Pi Yes Yes
M2Mqtt Any .NET platform (.NET Framework, .NET Compact Framework, .NET Micro Framework), WinRT
Machine Head Leiningen 2[94]
mosquitto C90, Linux, Unix, macOS, Windows, Raspberry Pi Yes Yes
MQTT-C ANSI C (C89)
Platform agnostic (in use in bare metal, Linux, macOS, and Windows applications)
Network IO callbacks Yes. Also supports single-thread applications.[95] Yes Yes
net-mqtt GHC Yes Yes Yes
Paho MQTT ANSI C (for C client),
C++11 (for C++ client),
JVM or Android (for Java client)
For C, C++ clients For C, C++ clients
SharkMQTT ANSI C (C89)
Platform agnostic (in use in bare metal, RTOS, HLOS))
Yes Yes Yes
wolfMQTT C89 Network IO callbacks Yes Yes Yes
eMQTT5 Linux, Unix, macOS, Windows, ESP32, STM32 (with lwIP and Mbed TLS) C++11 BSD socket implementation Yes Yes Yes
Bevywise MQTTBroker Linux, Unix, macOS, Windows, Raspberry Pi Yes
MqttDesk Linux, Unix, macOS, Windows, Raspberry Pi

General requirements

The following table shows various requirements that may be useful when deciding on which implementation to use for a device.

Implementation Build tools Platform requirements Supported operating systems
Adafruit IO
Amlen Make, Ant Linux CentOS, Red Hat Enterprise Linux
EMQX Erlang/OTP R19+ (when building from source)[93] Linux, Unix, macOS, Windows, Raspberry Pi[93] CentOS, Debian, Docker, macOS, Ubuntu, Red Hat Enterprise Linux, Windows 10, Windows 7, Raspbian (Raspberry Pi OS)[96]
FairCom Edge Visual Studio, Make, CMake, gcc C compiler (ANSI C/C89 or later) Linux, macOS, Windows, Raspbian (Raspberry Pi OS), Android
flespi N/A (it's cloud-based)
HiveMQ Linux, Unix, macOS, Windows, Raspberry Pi CentOS, Debian, Docker, Ubuntu, Red Hat Enterprise Linux, macOS, Windows 10, Windows 7, Raspbian (Raspberry Pi OS)
IBM WIoTP Message Gateway Linux CentOS, Docker, Red Hat Enterprise Linux
JoramMQ Maven, Java Linux, Unix, macOS, Windows, Raspberry Pi CentOS, Debian, Docker, Ubuntu, Red Hat Enterprise Linux, macOS, Windows 10, Windows 7, Raspbian (Raspberry Pi OS)
KMQTT Gradle, Kotlin Linux, JVM, Windows, Raspberry Pi Linux, Windows
M2Mqtt Visual Studio Any .NET platform (.NET Framework, .NET Compact Framework, .NET Micro Framework),
WinRT
Windows 98 or later, Windows Phone 8.1[29]
Machine Head Maven, Leiningen Leiningen 2[94] macOS, Linux (specific mentions of Debian, Ubuntu)[97]
mosquitto Make, CMake C90 BSD, Linux, macOS, QNX, Windows[98]
MQTT-C Make (optional)
CMake (optional)
C compiler (ANSI C/C89 or later) Bare metal, Linux, macOS, Windows
net-mqtt stack GHC
Paho MQTT Autotools, CMake, gmake, gcc, g++ or clang++ for C++ clients, Maven for Java clients ANSI C (for C client),
C++11 (for C++ client),
JVM or Android (for Java client)
Varies upon language. Please see official Eclipse Paho MQTT Download page here .
Solace PubSub+ Linux, macOS, Windows CentOS, Debian, Docker, KVM, Ubuntu, Red Hat Enterprise Linux, macOS, Windows 10, Windows 7; also Cloud[99]
SharkMQTT Any, including Make C compiler (ANSI C/C89 or later) Bare metal and all operating systems
wolfMQTT Autotools (autoconf, automake), Visual Studio, wolfSSL to enable extra features such as SSL/TLS support C89 Win32/64, Linux, macOS, 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, 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, [1], Green Hills INTEGRITY, Keil RTX, TOPPERS, PetaLinux, Apache Mynewt, PikeOS[59] (IDEs: Arduino, MPLAB Harmony[100])
eMQTT5 cmake, Mbed TLS to enable extra features such as SSL/TLS support C++11 Win32/64, Linux, macOS, FreeRTOS, FreeBSD, NetBSD, OpenBSD, embedded Linux, Yocto Linux,
Bevywise MQTTBroker Autotools , Visual Studio Linux, Unix, macOS, Windows, Raspberry Pi CentOS, Debian, Docker, KVM, Ubuntu, Red Hat Enterprise Linux, macOS, Windows32/64, Windows Server, Raspberry Pi, also Cloud
OpenHAB Eclipse Java build system Linux, Unix, macOS, Windows, Raspberry Pi CentOS, Debian, Ubuntu, Red Hat Enterprise Linux, macOS, Windows32/64, Raspberry Pi
MqttDesk Linux, Unix, macOS, Windows, Raspberry Pi CentOS, Debian, macOS, Ubuntu, Red Hat Enterprise Linux, Windows 10, Windows 7, Raspberry Pi OS
MQTTnet Visual Studio .NET Framework Windows

References

  1. "ISO/IEC 20922:2016 Information technology – Message Queuing Telemetry Transport (MQTT) v3.1.1". International Organization for Standardization. June 15, 2016. https://www.iso.org/standard/69466.html. 
  2. "Overview". https://learn.adafruit.com/welcome-to-adafruit-io?view=all#library-documentation-3001005-5. 
  3. "Adafruit IO REST API Documentation". https://io.adafruit.com/api/docs/#!/v2. 
  4. "Amlen". https://eclipse.org/amlen. 
  5. "Azure Event Grid REST API Documentation". https://learn.microsoft.com/en-us/rest/api/eventgrid/. 
  6. "EMQX". https://www.emqx.io. 
  7. "EMQ X- Erlang MQTT Broker — EMQ X - Erlang MQTT Broker 3.0 documentation". https://www.emqx.io/docs/en/v3.0/. 
  8. "EMQX 5.3.1 Changelogs". https://www.emqx.com/en/changelogs/broker/5.3.1. 
  9. "EMQX Enterprise". https://www.emqx.com/en/products/emqx. 
  10. "EMQX Enterprise 5.3.1 Changelogs". https://www.emqx.com/en/changelogs/enterprise/5.3.1. 
  11. "Secure MQTT 5 Client" (in en-US). https://realtimelogic.com/products/lua-mqtt/. 
  12. "Real Time Logic". https://realtimelogic.com/. 
  13. "NanoMQ". https://nanomq.io. 
  14. "MQTT X". https://mqttx.app. 
  15. "FairCom EDGE IIoT Integration Hub". https://www.faircom.com/products/faircomedge-iiot-integration-hub. 
  16. "FairCom EDGE V3 Resource Kit now available". 2020-11-08. https://www.faircom.com/insights/faircomedge-v3-resource-kit-now-available. 
  17. "FlashMQ MQTT server". https://www.flashmq.org/. 
  18. "flespi MQTT broker". https://flespi.com/mqtt-broker. 
  19. "HiveMQ MQTT Client". 10 November 2021. https://github.com/hivemq/hivemq-mqtt-client. 
  20. "HiveMQ MQTT Client 1.3.1". https://github.com/hivemq/hivemq-mqtt-client/releases/tag/v1.3.1. 
  21. "HiveMQ Community Edition". 21 July 2022. https://github.com/hivemq/hivemq-community-edition. 
  22. "HiveMQ CE 2024.1". https://github.com/hivemq/hivemq-community-edition/releases/tag/2024.1. 
  23. "HiveMQ". https://www.hivemq.com. 
  24. "What's new in HiveMQ 4.24?". https://www.hivemq.com/blog/whats-new-in-hivemq-4-24/. 
  25. "WIoTP Message Gateway". 9 November 2020. https://www.ibm.com/developerworks/downloads/iot/messagegateway/index.html. 
  26. "JoramMQ". http://mqtt.jorammq.com. 
  27. Pianca, Davide (2020-07-05), davidepianca98/KMQTT, https://github.com/davidepianca98/KMQTT, retrieved 2020-07-06 
  28. "Release 0.4.1 · davidepianca98/KMQTT" (in en). https://github.com/davidepianca98/KMQTT/releases/tag/0.4.1. 
  29. 29.0 29.1 29.2 "Eclipse Paho M2Mqtt". http://www.eclipse.org/paho/clients/dotnet/. 
  30. "M2MQTT Releases". https://github.com/eclipse/paho.mqtt.m2mqtt/releases. 
  31. 31.0 31.1 "Machine Head". http://clojuremqtt.info. 
  32. "ClojureWerks". http://clojurewerkz.org. 
  33. "Mongoose networking library for C/C++" (in en). https://mongoose.ws/. 
  34. "Mongoose :: Examples :: MQTT Client" (in en). https://mongoose.ws/tutorials/mqtt-client/. 
  35. "Mongoose :: Examples :: MQTT Server" (in en). https://mongoose.ws/tutorials/mqtt-server/. 
  36. "moquette". 11 November 2021. https://github.com/andsel/moquette. 
  37. "moquette Releases". https://github.com/moquette-io/moquette/releases. 
  38. "Mosquitto". https://mosquitto.org. 
  39. "Mosquitto ChangeLog.txt". 3 March 2023. https://github.com/eclipse/mosquitto/blob/master/ChangeLog.txt. 
  40. "MQTT🤖 Home". 2 October 2021. https://github.com/pascaldekloe/mqtt. 
  41. "MQTT-C". 10 November 2021. https://github.com/LiamBindle/MQTT-C. 
  42. "MQTT-C Releases". https://github.com/LiamBindle/MQTT-C/releases. 
  43. "mqttools". 2 November 2021. https://github.com/eerimoq/mqttools. 
  44. "net-mqtt: An MQTT Protocol Implementation.". https://hackage.haskell.org/package/net-mqtt. 
  45. "MQTT broker". https://github.com/openremote/openremote/wiki/How-to-work-with-MQTT. 
  46. 46.0 46.1 "Paho". http://www.eclipse.org/paho/. 
  47. "Eclipse Distribution License - v 1.0". http://www.eclipse.org/org/documents/edl-v10.php. 
  48. "Eclipse Paho Downloads - MQTT Client Comparison". http://www.eclipse.org/paho/index.php?page=downloads.php. 
  49. "Latest Releases". 21 November 2017. https://projects.eclipse.org/projects/iot.paho/releases/1.4.0-photon. 
  50. "Solace PubSub+". https://www.solace.com. 
  51. "APIs & Protocols" (in en-US). https://solace.com/products/apis-protocols/. 
  52. "Reference Information". https://docs.solace.com/quick-links-reference.htm. 
  53. "Event Broker Features". https://docs.solace.com/Release-Notes/Release-Info-appliance-sw-releases.htm#releaseSWAPP98. 
  54. "SharkMQTT Client Library" (in en-US). https://realtimelogic.com/products/sharkmqtt/. 
  55. "Real Time Logic". https://realtimelogic.com/. 
  56. "Home" (in en-gb). https://thingstream.io/. 
  57. "DOCS - Release notes" (in en-US). https://sites.google.com/thingstream.io/docs/release-notes. 
  58. "VerneMQ MQTT Broker". https://vernemq.com. 
  59. 59.0 59.1 59.2 59.3 "wolfMQTT Client Library" (in en-US). https://www.wolfssl.com/products/wolfmqtt/. 
  60. "wolfssl.com". https://www.wolfssl.com. 
  61. "wolfMQTT Changelog" (in en-US). https://www.wolfssl.com/docs/wolfmqtt-changelog/. 
  62. "eMQTT v5.0 Client Library". 15 September 2021. https://github.com/X-Ryl669/eMQTT5. 
  63. "Bevywise MQTT broker". https://www.bevywise.com/mqtt-broker/. 
  64. "MQTT client". https://www.openhab.org/addons/bindings/mqtt/. 
  65. "Waterstream". https://waterstream.io/. 
  66. "SimpleMatter". https://simplematter.io/. 
  67. "MQTTDESK MQTT Client". https://www.ioctrl.com/. 
  68. "MQTT For Sensor Networks (MQTT-SN) Protocol Specification Version 1.2". November 14, 2013. https://www.oasis-open.org/committees/download.php/66091/MQTT-SN_spec_v1.2.pdf. 
  69. "MQTT V3.1 Protocol Specification". 2010. http://public.dhe.ibm.com/software/dw/webservices/ws-mqtt/mqtt-v3r1.html. 
  70. Andrew Banks; Rahul Gupta, eds (29 October 2014). "MQTT Version 3.1.1". OASIS. http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html. 
  71. Andrew Banks; Rahul Gupta, eds (10 December 2015). "MQTT Version 3.1.1 Plus Errata 01". OASIS. http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/mqtt-v3.1.1.html. 
  72. Andrew Banks; Ed Briggs; Ken Borgendale et al., eds (25 December 2017). "MQTT Version 5.0". OASIS. http://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.html. 
  73. "FAQ - Frequently Asked Questions" (in en-US). http://mqtt.org/faq. 
  74. "Azure Event Grid MQTT broker". https://learn.microsoft.com/en-us/azure/event-grid/mqtt-support. 
  75. "HTTP Plug-in". https://docs.faircom.com/doc/integration_hub_reference/HTTPPlug-in.htm. 
  76. 76.0 76.1 "MQTT 5.0 compliance checklist". https://flespi.com/mqtt-broker#mqtt-checklist. 
  77. "HiveMQ 4.1". https://www.hivemq.com/blog/hivemq-4-1-released/. 
  78. "Moquette Documentation - SSL Configuration". https://moquette-io.github.io/moquette/documentation.html#_ssl_configuration. 
  79. "mosquitto.conf(5)". 3 November 2021. https://mosquitto.org/man/mosquitto-conf-5.html. 
  80. "Eclipse Paho - MQTT-SN Transparent Gateway". https://www.eclipse.org/paho/index.php?page=components/mqtt-sn-transparent-gateway/index.php. 
  81. "Eclipse Paho 1.4.0 (Photon)". 21 November 2017. https://projects.eclipse.org/projects/iot.paho/releases/1.4.0-photon. 
  82. "Open APIs & Protocols". https://docs.solace.com/Open-APIs-Protocols/Open-APIs-Protocols.htm. 
  83. "MQTT 5.0 Support 🎉". 4 January 2021. https://solace.community/discussion/comment/2326#Comment_2326. 
  84. "IBM Knowledge Center" (in en-US). https://www.ibm.com/support/knowledgecenter/SSMKHH_10.0.0/com.ibm.etools.mft.doc/bc62020_.htm. 
  85. "MQTT API". https://learn.adafruit.com/adafruit-io/mqtt-api#publish-qos-levels. 
  86. "Amlen". https://eclipse.org/amlen. 
  87. "Azure Event Grid MQTT broker". https://learn.microsoft.com/en-us/azure/event-grid/mqtt-overview. 
  88. "EMQX 3.0 documentation". https://www.emqx.io/docs/en/v3.0/. 
  89. "Quality of Service 0,1 & 2 - MQTT Essentials: Part 6". https://www.hivemq.com/blog/mqtt-essentials-part-6-mqtt-quality-of-service-levels/. 
  90. Selva, Andrea (2018-01-29), moquette: Java MQTT lightweight broker, https://github.com/andsel/moquette, retrieved 2018-02-01 
  91. "mosquitto.conf". https://mosquitto.org/man/mosquitto-conf-5.html. 
  92. "Solace Documentation - Quality of Service Levels supported". https://docs.solace.com/Open-APIs-Protocols/MQTT/Using-MQTT.htm#Quality. 
  93. 93.0 93.1 93.2 EMQX GitHub, EMQX, 2018-09-30, https://github.com/emqx/emqx, retrieved 2018-09-30 
  94. 94.0 94.1 machine_head: Clojure MQTT client, ClojureWerkz, 2017-11-29, https://github.com/clojurewerkz/machine_head, retrieved 2017-12-13, "Machine Head uses Leiningen 2. Make sure you have it installed and then run tests against supported Clojure versions using..." 
  95. "MQTT-C single-threaded applications". https://liambindle.ca/MQTT-C/group__api.html#gae3d3aafc7588ed53a90c9f66fc620a6e. 
  96. emqx.io, feng at. "EMQ X- Downloads". https://www.emqx.io/downloads. 
  97. "Getting Started with MQTT and Clojure" (in en). http://clojuremqtt.info/articles/getting_started.html. 
  98. "Downloads" (in en-US). https://mosquitto.org/download/. 
  99. "Solace PubSub+ Cloud". https://cloud.solace.com. 
  100. "wolfMQTT User Manual - 2.4 Building on Other Systems". 2018-05-25. https://www.wolfssl.com/docs/wolfmqtt-manual/#h.hknjshj7vt9e.