We are pleased to announce the approval and publication of a new Committee Specification by the members of the OASIS Message Queuing Telemetry Transport (MQTT) TC:
MQTT Version 3.1.1
Committee Specification 01
18 May 2014
MQTT is a Client Server publish/subscribe messaging transport protocol. It is light weight, open, simple, and designed so as to be easy to implement. These characteristics make it ideal for use in many situations, including constrained environments such as for communication in Machine to Machine (M2M) and Internet of Things (IoT) contexts where a small code footprint is required and/or network bandwidth is at a premium.
The protocol runs over TCP/IP, or over other network protocols that provide ordered, lossless, bi-directional connections. Its features include:
– Use of the publish/subscribe message pattern which provides one-to-many message distribution and decoupling of applications.
– A messaging transport that is agnostic to the content of the payload.
– Three qualities of service for message delivery:
— “At most once”, where messages are delivered according to the best efforts of the operating environment. Message loss can occur. This level could be used, for example, with ambient sensor data where it does not matter if an individual reading is lost as the next one will be published soon after.
— “At least once”, where messages are assured to arrive but duplicates can occur.
— “Exactly once”, where message are assured to arrive exactly once. This level could be used, for example, with billing systems where duplicate or lost messages could lead to incorrect charges being applied.
– A small transport overhead and protocol exchanges minimized to reduce network traffic.
– A mechanism to notify interested parties when an abnormal disconnection occurs.
The prose specification and related files are available here:
Editable source (Authoritative):
Distribution ZIP files
For your convenience, OASIS provides a complete package of each prose specification and related files in a ZIP distribution file. You can download the ZIP files here:
Members of the ASIS Message Queuing Telemetry Transport (MQTT) TC  requested a Special Majority Vote to approve this specification as a Committee Specification. The specification had been released for public review as required by the TC Process . The vote to approve as a Committee Specification passed , and the approved CS01 is now available online in the OASIS Library as referenced above.
Our congratulations to the TC on achieving this milestone.
========== Additional references:
 ASIS Message Queuing Telemetry Transport (MQTT) TC
 Public reviews:
30-day public review, 10 January 2014:
— Comment resolution log:
15-day public review, 21 April 2014:
— Comment resolution log:
 Approval ballot: