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The most advanced MQTT debugging software

MQTT has been used for many years as a message protocol for machine communication and is now the defacto standard for (I)IoT communication and information exchange in the Industry. Since 2013 MQTT is standardized as IoT protocol by the Organization for the Advancement of Structured Information Standards (OASIS). In 2014 our software MQTT.fx® has also been introduced first time to the community..

Today MQTT.fx® 5 is our tool for testing IoT routes in development and production. It allows you to connect to the development and/or production broker and test your project before you start writing code for it. Since you can run these test cases without programming, this not only means a significant reduction of manual work for you, but also an exceptional increase in the quality of your software.

MQTT.fx® 5.x

MQTT.fx the Swiss Army Knife for MQTT Messaging. No matter if you are a developer, employee of a large IoT department, or hobbyist. We have the right option for everyone who builds software that talks to machines. Since the possibility to test the machine communication not only saves you a lot of time, but also gives you a high flexibility in your work, we have taken MQTT.fx® to the next level.

Eclipse Sparkplug Explorer & Editor

The Sparkplug Message Explorer receives all Sparkplug Messages. Messages are decoded and displayed as forrmatted JSON and the topics are shown in structured tree view.
With the Sparklug Editor you can create virtual EoNs (Sparkplug Edge of Network Nodes) and add compile Sparkplug Payload and different message types (included Metrics + Properties). Spakrplug Messags can ne previewed and published. 

Pluggable Payload Decoder

Recevied MQTT messages are displayed decoded based on the choosen Payload Decoder. MQTT.fx® comes with a set of default Payload Decoders („Plain Text“, „JSON Pretty Format“, „Base64“, „Hex“, „Hex Pretty Format“, „Binary“ „Msgpack“, „Sparkplug“, „Sparkplug Pretty Format“)  
MQTT.fx® supports a Payload Decoder interface that also allows to add custom decoder to your needs (https://github.com/Jerady/mqttfx-payload-decoders).

Topic Collector & Explorer

The MQTT.fx® Topic Explorer scans for active topics (topics that are in action or have stored retained messages).

Detected topics are stored in an alphabetically orderd list. You can instantly subscribe to a collected topic on double click, also the topic list can be copied for futher processing to your needs.

  • Connection Profiles: all Parameters of a reusable MQTT Broker connection (Broker Address 
    Broker Port, Client ID, MQTT Version, Security Settings,....) are stored and selectable by given profiles name.
  • Scripted MQTT messaging allows scripted messages publishing and receiving via the GraalVM JS Engine (JavaScript, ECMAScript). Precoded scripts can be chosen from Drop-Down to be excecuted and can on demand be edited by default system editor (default), or by a chosen editor.  Execusion output is shown instantly in the scripting debugging console.
  • The Logging Console shows events going on inside of MQTT.fx and gives more detailed insights of the MQTT communication flow.
  • Broker Status: Brokers like mosquitto or HiveMQ support the unofficial “$SYS” topics to provide some insights of broker values – needs to be enabled on the broker 
  • Security: Username/Password authentication; TLS/SSL support:  Protocol Versions: all TLS versions up to TLS 1.3 are supported, Key Algorithms: RDA (Rivest–Shamir–Adleman, EC (Elliptic Curve).
  • Published Messages: Topic Name, QoS 0-2, Retained Flag, User Properties (MQTT v5.0), Content Type (MQTT v5.0), Payload Content (UTF-8 String, MQTT v5.0), Pluggable Payload Editor UI (https://github.com/Jerady/mqttfx-addon-payload-editors) 
  • Published Messages History: re-publish previous send messages (not persisted)
  • Received Messages: color coded table of received messages (Seq#, Received Time, Topic Name, QoS, Retained), Flexible filter option to filter messages by keyword (also Payload is included), Message Value Fields: Topics Name, Matching Topics Context (Wildcards), Payload, Content Type (MQTT5), User Properties (MQTT5), Seq Number, Received Time, QoS, Retained Flag, Duplicate Flag, Payload auto decoding

Free Trial

We offer a free one-month trial to test MQTT.fx®.
No automatic renewals, no costs, no spam.

Just MQTT.fx® full feature set.

Software made in Germany



  • Non commercial use only
  • Single private user
  • One time payment
  • VAT included
  • Full feature set of MQTT.fx®5.x

49,90 EUR

  • Secure checkout and payment


  • Commercial use
  • One concurrent user
  • Yearly subscription
  • VAT excluded
  • Full feature set of MQTT.fx®5.x
  • Support

220,00 EUR

  • Secure checkout and payment


  • Commercial use
  • Five concurrent user
  • Yearly subscription
  • VAT excluded
  • Full feature set of MQTT.fx®5.x
  • Support

650,00 EUR

  • Secure checkout and payment


  • Commercial use
  • Unlimited user access
  • Yearly subscription
  • VAT excluded
  • Full feature set of MQTT.fx®5.x
  • Support

1.900,00 EUR

  • Secure checkout and payment

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