# MQTT Version 3.1.1 Protocol

**Canonical:** https://apis.io/apis/mqtt/protocol-v3-1-1/  
**Provider:** MQTT — https://apis.io/providers/mqtt/  
**Base URL:** mqtt://broker.example.com:1883  
**Documentation:** https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html

MQTT Version 3.1.1 Protocol is one of 2 APIs that [MQTT](https://apis.io/providers/mqtt/) publishes on the [APIs.io](https://apis.io/) network. Tagged areas include MQTT 3.1.1, Protocol, Publish Subscribe, OASIS, and IoT.

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.

## Machine-readable artifacts (2)

- **Specification** — https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html
- **Specification PDF** — https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.pdf

## Other MQTT APIs (1)

- [MQTT Version 5.0 Protocol](https://apis.io/apis/mqtt/protocol-v5/)

## Tags

MQTT 3.1.1, Protocol, Publish Subscribe, OASIS, IoT

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/mqtt/protocol-v3-1-1/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/mqtt/.