Legacy MQTT.fx downloads and MQTT testing guides
Pick the right MQTT.fx installer for your operating system.
MQTT.fx is still useful when an IoT support note, test script, or team runbook expects the older desktop client. It can connect to a broker, subscribe to a topic, publish a payload, and verify credentials without writing code.
For new workflows, compare MQTT.fx with MQTTX and MQTT Explorer before standardizing on a client. Legacy convenience should not become a permanent tooling constraint.
On Linux, choose the package format that matches your distribution. Debian and Ubuntu users normally want the 64-bit DEB package. Fedora, RHEL, and CentOS users normally want the 64-bit RPM package.
On macOS, newer security prompts may require opening the app from Finder the first time. If MQTT.fx does not fit the current system, use MQTTX as the modern fallback.
Use this installer on modern 64-bit Windows desktops.
Download .exeUse this disk image for Intel-era MQTT.fx desktop setups.
Download .dmgUse this package for 64-bit Debian, Ubuntu, Linux Mint, and related distributions.
Download .debUse this package for RPM-based 64-bit Linux distributions.
Download .rpmOnly use this when maintaining older 32-bit machines.
Download .debOnly use this for legacy 32-bit RPM-based Linux systems.
Download .rpmDownload the 64-bit DEB package, install it with your system package tool, then launch MQTT.fx and create a broker connection with host, port, username, password, and TLS settings if required.
Create a broker profile, connect, subscribe to a topic filter, then publish a test payload to the same or related topic to verify broker behavior.
MQTT.fx has been widely searched as a free MQTT client, but users should verify license terms for their own use case and consider modern actively maintained alternatives.