Free Public MQTT Broker.
Connect to a free, always-on MQTT broker for learning, testing, and prototyping. No signup — use for basic testing and development.
Connection Details
Broker URL
:broker.freemqtt.com
Port (TCP)sdad
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:1883
Port (SSL/TLS)
:8883
WebSocket URL (WS)
:ws://broker.freemqtt.com:8083/mqtt
WebSocket URL (WSS)
:wss://broker.freemqtt.com:8084/mqtt
Username
:freemqtt
Password
:public
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Service Policy
Terms, limits, and reporting info for the free public MQTT broker — not intended for production use.
Purpose & Scope
FreeMQTT is a public, free broker for learning, testing, and prototyping only — not for production, staging, or UAT.
Application for Other Web Presence and Media
All policies apply equally to our web presence on third-party platforms (e.g., GitHub, X, LinkedIn) as well as to our newsletter.
Reliability & Limits
Expect flakiness: No SLA — servers may be updated or restarted, retained messages can be lost, and connections can drop. Implement reconnect/backoff logic and don’t rely on durability.
Usage Rules & Fair Use
Play nice: No illegal activity, spam, crypto-mining, or attempts to overload the service. Keep message sizes small and avoid excessive simultaneous connections.
Enforcement & Liability
We can act: We reserve the right to disconnect or block abusive clients/IPs. The broker is provided “as-is” — no warranties or uptime guarantees; liability is limited to the extent permitted by law.
Contact & Abuse Reporting
Report problems: For abuse or urgent issues email support@zunoy.com. For general issues contact support.
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Use Cases of Public MQTT Broker
Explore practical ways to use FreeMQTT for testing, learning, and rapid prototyping — no setup, no friction.
IoT Device Testing
Quickly test sensors, microcontrollers, and IoT devices without setting up your own infrastructure.
MQTT Learning & Education
Learn MQTT fundamentals publish, subscribe, inspect messages and experiment with topic, QoS & retained flags.
Application Prototyping
Prototype real-time apps and dashboards using live data and validate functionality before moving to production.
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Get Started with FreeMQTT
Copy-paste connection examples for popular tech stacks. All examples use TLS/SSL ports for secure connections.
Node.js (MQTT.js)Arduino / C++WebSocket (Browser)GolangPython (PAHO MQTT)
Copy code
1const mqtt = require('mqtt');
2const client = mqtt.connect('mqtts://mqtt.freemqtt.com:8883');
3
4client.on('connect', () => {
5 client.subscribe('test/topic');
6 client.publish('test/topic', 'Hello from Node.js');
7});
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Best Practices Guide
Follow these guidelines for reliable testing and to avoid common pitfalls when using our free broker.
Feature
Good Practice
Avoid
Client ID
Use unique client IDs per device/session.
Reusing generic IDs causes collisions and disconnects.
TLS / Security
Use TLS on port 8883 or WSS.
Sending sensitive data over plaintext ports (1883/ws).
Reconnect / Backoff
Implement exponential backoff with randomized jitter.
Immediate retries without backoff; risk of hammering.
Payload size
Keep payloads under 64 KB to reduce latency.
Sending large binary blobs causes latency and failures.
QoS
Prefer QoS 0/1 for typical test messages.
Blindly using QoS 2 increases complexity and overhead.
Retained messages
Avoid retained messages for ephemeral testing workflows.
Relying on retained messages causes stale-state problems.
Topic namespace
Use hierarchical topics like dev//sensor consistently.
Publishing to flat topics causes collisions and confusion.
Last Will (LWT)
Set concise Last Will topic and payload.
No LWT makes unexpected disconnects hard to detect.
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Key Features of Public FreeMQTT Broker
Everything you need for seamless MQTT testing and development, available instantly.
Instant Access
No registration or setup required - start testing in seconds
Always-On Broker
Hosted on reliable cloud infrastructure with automatic restarts and periodic maintenance for stability.
Free & Public
Completely free to use for learning, research, and prototyping — no account or hidden limits.
Global Access
Accessible worldwide — test from microcontrollers, web apps, or cloud systems without location restrictions.
Multi-Protocol Support
Supports MQTT v3.1, v3.1.1, and v5 over TCP, WebSocket, and secure TLS/WSS connections.
Stable & Reliable
Backed by robust infrastructure to ensure consistent uptime and minimal latency during peak usage.
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More Free Developer Tools
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ShareIPA
Upload and distribute iOS IPA & Android APK files instantly. Share installer links with one click
Find My UDID
Retrieve your iOS UDID instantly for development provisioning and device management.
Free MockAPI
Instant mock endpoints and sample JSON for frontend testing and prototyping.
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Frequently asked questions
Is this really free with no hidden costs?
Yes, completely free for development and testing. No credit card required, no surprise fees.
Can I use this for production applications?
No, this is strictly for testing and development. For production use, check out Zunoy's enterprise plans.
What are the connection limits?
We enforce fair-use limits to ensure service quality. Most testing use cases won't hit them.
Do you support MQTT 5.0 features?
Yes! Full MQTT 3.1.1 and 5.0 protocol support including all new 5.0 features.
How reliable is the service?
This is a best-effort service with no SLA. We recommend implementing reconnect logic in your clients.
Is my data secure and private?
This is a public broker — assume all topics and messages are visible to others. Use TLS ports for encryption.
What happens if I abuse the service?
We monitor for abuse and may block IPs or clients that violate our usage policies.
Who runs FreeMQTT.com?
This is a community service sponsored by Zunoy to help developers learn and test MQTT.
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Zunoy — Built for Builders
FreeMQTT is one of our free developer tools. For production needs, see our paid SaaS platform with enterprise reliability and support.
UptimeFormAPI
MockAPI
Authenticator
Appshare
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FreeMQTT
Powered by Zunoy
Free public MQTT broker for testing - no signup required
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All rights reserved. All tools under the Zunoy Suite are owned, maintained, and operated by Mentcube Technologies Pvt. Ltd. v0.1.0
For legal information, including Terms of Service, Privacy Policy, and Acceptable Use Policy, visit zunoy.com/legal. By using this site, you agree to our use of cookies and similar technologies as described in our policies.
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