# MQTTool

> MQTT client and test tool for IoT and M2M messaging. (iPhone/iPad app by Brent Petit.)

- Source: https://appshunter.io/ios/app/mqttool/id1085976398 (this page in markdown: same URL + `.md`)
- Developer: [Brent Petit](https://appshunter.io/developer/1085976397)
- Category: Utilities, Education
- Price: Free
- Rating: 4.31/5 from 26 App Store ratings · 37 written reviews indexed
- Age rating: 4+
- Requires: iOS 10.0 · 18 MB
- Languages: English
- Released: 2016-02-25
- Data updated: 2026-06-10
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/mqttool/id1085976398/reviews.md

## What is MQTTool?

This is an MQTT client and test tool. MQTT is a machine-to-machine (M2M) messaging protocol commonly used for IoT applications. For more information on MQTT visit http://mqtt.org

MQTTool can connect to authenticated and unauthenticated MQTT brokers, subscribe to topics, and publish messages to topics.

I built this tool as i was doing my own MQTT investigations and I've posted it hoping others would find it useful too. I continue to use it on projects, and I'm continuing to look to improve this tool. If there are changes that would make this more useful, please send me feedback. Thanks!

## Key features

- MQTT client functionality
- Connect to authenticated brokers
- Connect to unauthenticated brokers
- Subscribe to topics
- Publish messages to topics
- IoT application testing

## Recent user reviews (10 of 37)

All indexed reviews: https://appshunter.io/ios/app/mqttool/id1085976398/reviews.md

### 5/5 — Very nice simple app

*2025-06-25, version 2.6*

I was able to connect to my local ESP32 server, subscribe to topics and publish on topics.

The interface is very intuitive.

I would suggest one improvement - option to publish in JSON format.

I published a message in JSON format but it was not recognized by the server.

It would be great to add JSON format.

I commend you for this very nice app !!!

Thanks :)

### 1/5 — wont allow me to enter subscription

*2024-01-14, version 2.6*

does not open virtual keyboard when touching the field on iphone

### 5/5 — Top

*2023-07-06*

Ein sauber programmiertes Tool zum Testen von MQTT Projekten.

### 1/5 — Couldn’t get it work

*2022-11-09, version 2.6*

Couldn’t get it to work. Bummer huh?

### 5/5 — Очень неплохо

*2022-10-23*

Для теста сервера очень удобное приложение. Спасибо разработчикам.

### 5/5 — Exactly the Right Tool!

*2021-09-05, version 2.6*

I’m just starting to understand the MQTT side of smart devices and this app I had connected and sending & receiving on all first attempts. Very user friendly!

### 4/5 — Sehr nützlich und schlank ohne Werbung

*2020-08-29*

Muss leider einen Stern abziehen, da die Funktionen Save Password nicht korrekt funktioniert. Bei jedem Neustart der App muss man den Haken wieder erneut setzen.
Vergisst man das, ist das Passwortfeld beim nächsten Start leer.

The Save Password function does not work correctly. Each time you restart the app you have to tick the box again.
If you forget that, the password field will be empty the next time you start.

### 1/5 — Leider unbrauchbar

*2020-04-26*

Kann mich nicht per ip mit meinem Server verbinden und daher ist es für mich unbrauchbar.

### 1/5 — Unable to connect to server

*2020-03-25, version 2.6*

It won’t connect to my server. I am using the same credentials and settings as I use in an app on my laptop. Just won’t connect

### 5/5 — Отлично

*2020-01-09*

Делайте больше фич и платную версию!

## Frequently asked questions about MQTTool

### What does MQTTool do?

MQTTool functions as an MQTT client and test tool. It enables users to connect to MQTT brokers, subscribe to various message topics, and publish messages to those topics. This is particularly useful for testing and developing Internet of Things (IoT) applications.

### What are the key features of MQTTool?

Key features include the ability to connect to both authenticated and unauthenticated MQTT brokers, subscribe to specific message topics to receive data, and publish messages to topics for sending data. It's designed for machine-to-machine (M2M) messaging and IoT investigations.

### Is MQTTool free to use?

Yes, MQTTool is provided as a free application. There are no in-app purchases or advertisements mentioned, indicating it is completely free for users.

### Who is the target audience for MQTTool?

This tool is built for individuals involved in MQTT investigations, IoT projects, and machine-to-machine (M2M) communication. Developers and testers working with IoT applications will find it particularly useful.

### What is MQTT and why is this tool useful for it?

MQTT is a machine-to-machine messaging protocol commonly used for IoT applications. This tool is useful because it provides a direct interface to connect to MQTT brokers, allowing you to test subscriptions and message publishing, which are core functionalities of MQTT-based systems.

## Version history (last 5 releases)

### 2.6 — 2019-04-10

MQTTool source has been released on GitHub.
See https://github.com/bjpetit/MQTTool for more details.

This update includes some minor layout fixes.

### 2.5 — 2018-10-22

Bug fixes and some minor UI cleanup.

### 2.4.1 — 2018-07-01

Fixes for a couple of bugs.

### 2.4 — 2018-05-11

Idle Sleep Delay
- If your device is a bit too aggressive about going to sleep while you are trying to use this tool, this option is for you. A new toggle switch can be found under the MQTTool App Settings. If you enable this switch, the device will wait 5 minutes before automatically going to sleep. Note: This sleep delay will only be in effect while the MQTTool app is open, connected to a broker and subscribed to a topic. Otherwise the device's default sleep timer applies.

Fixed an input validation bug in the connect tab

### 2.3 — 2018-03-29

This release fixes a few bugs.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*