---
title: "Python MQTT Example: Connect, Publish and Subscribe | ConnectMQ"
description: "Python MQTT client example with paho-mqtt 2.x: copy-paste code for the free public broker broker.connectmq.com and a secure TLS connection to ConnectMQ."
url: "https://connectmq.com/code-samples/python/"
language: "en"
---

Code samples

# Python MQTT example

Connect Python to an MQTT broker with paho-mqtt. Start on the free public broker, then point the same code at a secure private broker on ConnectMQ.

Library

[paho-mqtt 2.x](https://pypi.org/project/paho-mqtt/)

Install

`pip install "paho-mqtt>=2.0"`

[**Source code on GitHub**`mqtt-code-samples/python`Clone the complete, runnable examples. Stars and pull requests welcome. View on GitHub](https://github.com/connectmq/mqtt-code-samples/tree/main/python)

## 1\. Try it on the free public broker

No account needed: connect to `broker.connectmq.com` on port 1883 and start publishing in seconds.

main.py

```
import json
import paho.mqtt.client as mqtt

TOPIC = "your-project/sensors/temperature"  # Use a unique topic prefix: everyone can read the public broker

# Runs when the connection is established
def on_connect(client, userdata, flags, reason_code, properties):
    print("Connected:", reason_code)
    # Subscribe to the temperature topic
    client.subscribe(TOPIC, qos=1)
    # Publish a JSON reading
    client.publish(TOPIC, json.dumps({"temperature": 21.5}), qos=1)

# Runs for every message on a subscribed topic
def on_message(client, userdata, msg):
    print(msg.topic, msg.payload.decode())

client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2)
client.on_connect = on_connect
client.on_message = on_message

# Connect to the free public broker (no account needed)
client.connect("broker.connectmq.com", 1883)
# Keep the client running
client.loop_forever()
```

### Free public MQTT broker

The public broker is shared: anyone can subscribe to your topics. Never send passwords, personal data or anything confidential through it.

[About the free public MQTT broker](https://connectmq.com/public-mqtt-broker/)

## 2\. Go to production with ConnectMQ

For real devices, use a private serverless MQTT broker on ConnectMQ instead of the public one: TLS encryption, a username and password for every device and per-topic access control, fully managed. Start on the Free plan — no card required.

Replace YOUR\_BROKER\_HOST, YOUR\_USERNAME and YOUR\_PASSWORD with the values from your ConnectMQ dashboard.

[Start for free](https://app.connectmq.com/signup) [See pricing](https://connectmq.com/pricing/)

main.py

```
import json
import paho.mqtt.client as mqtt

TOPIC = "your-project/sensors/temperature"

# Runs when the connection is established
def on_connect(client, userdata, flags, reason_code, properties):
    print("Connected:", reason_code)
    # Subscribe to the temperature topic
    client.subscribe(TOPIC, qos=1)
    # Publish a JSON reading
    client.publish(TOPIC, json.dumps({"temperature": 21.5}), qos=1)

# Runs for every message on a subscribed topic
def on_message(client, userdata, msg):
    print(msg.topic, msg.payload.decode())

client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2)
client.on_connect = on_connect
client.on_message = on_message

# Username and password from your ConnectMQ dashboard
client.username_pw_set("YOUR_USERNAME", "YOUR_PASSWORD")
# TLS: the system CA store verifies the broker certificate
client.tls_set()

# Connect to your private ConnectMQ broker on port 8883
client.connect("YOUR_BROKER_HOST", 8883)
# Keep the client running
client.loop_forever()
```

## Python MQTT FAQ

How do I connect Python to an MQTT broker?

Install paho-mqtt 2.x, connect to the broker host on port 1883 (or 8883 with TLS), then subscribe to a topic and publish messages to it. The examples on this page connect to the free public broker broker.connectmq.com and to a private ConnectMQ broker.

Is there a free MQTT broker for testing Python?

Yes. broker.connectmq.com is a free public MQTT broker that needs no account. Anyone can read its topics, so use it only for tests and use a unique topic prefix.

How do I secure a Python MQTT connection?

Connect over TLS on port 8883 with a username and password from your ConnectMQ dashboard, and give every device its own credentials and topic permissions instead of using the public broker.

## More code samples

[

### Node.js

Connect Node.js to an MQTT broker with MQTT.js.

View example](https://connectmq.com/code-samples/nodejs/)[

### ESP32

Connect an ESP32 to an MQTT broker over Wi-Fi with the Arduino PubSubClient library.

View example](https://connectmq.com/code-samples/esp32/)[

### Go

Connect Go to an MQTT broker with the Eclipse Paho Go client.

View example](https://connectmq.com/code-samples/go/)[

### CLI (mosquitto)

Publish and subscribe from the command line with mosquitto\_pub and mosquitto\_sub.

View example](https://connectmq.com/code-samples/cli/)[

### Java

Connect Java to an MQTT broker with the Eclipse Paho Java client.

View example](https://connectmq.com/code-samples/java/)[

### C# (.NET)

Connect C# and .NET to an MQTT broker with MQTTnet.

View example](https://connectmq.com/code-samples/csharp/)[

### Rust

Connect Rust to an MQTT broker with the rumqttc crate.

View example](https://connectmq.com/code-samples/rust/)[

### Dart (Flutter)

Connect Dart and Flutter apps to an MQTT broker with the mqtt\_client package.

View example](https://connectmq.com/code-samples/dart-flutter/)[

### Swift / Kotlin

Connect native iOS (Swift) and Android (Kotlin) apps to an MQTT broker.

View example](https://connectmq.com/code-samples/swift-kotlin/)[

### Home Assistant

Connect Home Assistant to an MQTT broker and turn MQTT messages into sensors.

View example](https://connectmq.com/code-samples/home-assistant/)[

### Node-RED

Connect Node-RED to an MQTT broker with an importable flow.

View example](https://connectmq.com/code-samples/node-red/)

[All code samples](https://connectmq.com/code-samples/)

### Free public MQTT broker

Test any example on broker.connectmq.com — no sign-up, MQTT 3.1.1 and 5, TCP, TLS and WebSocket.

[About the free public MQTT broker](https://connectmq.com/public-mqtt-broker/)

### Secure serverless MQTT for production

When it is time for real devices, run the same code on a private, fully managed ConnectMQ broker with TLS and per-device credentials.

[Start for free](https://app.connectmq.com/signup)

## Your private MQTT broker is a few clicks away

Create an account, get your broker credentials and connect your first device — no servers to install, patch or scale.

[Get started](https://app.connectmq.com/signup) [See pricing](https://connectmq.com/pricing/)

## Articles

[All articles](https://connectmq.com/blog/)

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broker.connectmq.com is a free public MQTT broker for testing and learning. Here are the ports, the anonymous access rules, the limits and copy-paste examples for the CLI, Python, Node.js and the browser.

September 20, 20267 min read

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