aid: mqtt
name: MQTT
description: >-
  MQTT (Message Queuing Telemetry Transport) is an OASIS-standard, lightweight
  publish/subscribe messaging transport protocol designed for constrained
  devices and low-bandwidth, high-latency, or unreliable networks, making it
  the de-facto messaging protocol for IoT and machine-to-machine (M2M)
  communication. MQTT is a protocol specification rather than a hosted API:
  clients connect over TCP/TLS (typically port 1883 or 8883) or WebSocket
  (8080/8081) to an MQTT broker (such as Mosquitto, HiveMQ, EMQX, or AWS IoT
  Core) and exchange CONNECT, PUBLISH, SUBSCRIBE, and other control packets
  defined by the standard. The current standard is MQTT Version 5.0
  (OASIS Standard, 7 March 2019); MQTT 3.1.1 remains widely deployed.
type: Index
image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
tags:
  - MQTT
  - Messaging
  - Publish Subscribe
  - IoT
  - M2M
  - Protocol
  - OASIS Standard
  - Telemetry
url: >-
  https://raw.githubusercontent.com/api-evangelist/mqtt/refs/heads/main/apis.yml
created: '2026-05-11'
modified: '2026-05-11'
specificationVersion: '0.19'
apis:
  - aid: mqtt:protocol-v5
    name: MQTT Version 5.0 Protocol
    description: >-
      OASIS Standard publish/subscribe messaging protocol for IoT and M2M
      communication. MQTT v5.0 defines the wire format and behavior of
      CONNECT, PUBLISH, SUBSCRIBE, UNSUBSCRIBE, PINGREQ, DISCONNECT and other
      control packets exchanged between MQTT clients and brokers over TCP
      (typically 1883, or 8883 with TLS) or WebSockets. Authentication is
      broker-specific and may include username/password, X.509 client
      certificates, or OAuth/JWT enhanced authentication.
    humanURL: https://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.html
    baseURL: mqtt://broker.example.com:1883
    tags:
      - MQTT 5.0
      - Protocol
      - Publish Subscribe
      - OASIS
      - IoT
    properties:
      - type: Specification
        url: https://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.html
      - type: Specification PDF
        url: https://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.pdf
      - type: OASIS Standard Page
        url: https://www.oasis-open.org/standard/mqtt-v5-0-os/
      - type: Specifications Index
        url: https://mqtt.org/mqtt-specification/
  - aid: mqtt:protocol-v3-1-1
    name: MQTT Version 3.1.1 Protocol
    description: >-
      Previous OASIS Standard version of MQTT, still widely deployed across
      IoT brokers, devices, and cloud platforms. MQTT 3.1.1 defines the
      publish/subscribe messaging semantics, QoS levels 0/1/2, retained
      messages, and last-will-and-testament that are inherited and extended
      by MQTT 5.0.
    humanURL: https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html
    baseURL: mqtt://broker.example.com:1883
    tags:
      - MQTT 3.1.1
      - Protocol
      - Publish Subscribe
      - OASIS
      - IoT
    properties:
      - type: Specification
        url: https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html
      - type: Specification PDF
        url: https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.pdf

common:
  - type: Website
    url: https://mqtt.org
  - type: Specifications
    url: https://mqtt.org/mqtt-specification/
  - type: OASIS Technical Committee
    url: https://www.oasis-open.org/committees/tc_home.php?wg_abbrev=mqtt
  - type: Software Listings
    url: https://mqtt.org/software/

maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com