The best MQTT clients in 2026
An overview of the most popular MQTT clients in 2026 and who each suits.
MQTT Viewer is this site's app and comes first.
MQTT Viewer (fast, free, focused)
A free, open-source desktop client for macOS, Windows and Linux, built around a live topic tree. It adds a message timeline, message comparison, payload decoding, a searchable publish history, up to 10 connections and full MQTT v3.1.1 and v5.
Best for: a free, broker-neutral desktop tool for debugging traffic. Download it.
MQTT Explorer (the classic topic tree)
MQTT Explorer popularised the topic-tree view and remains a favourite in the Home Assistant community. It plots numeric topics and diffs messages, but connects to one broker at a time and has no MQTT 5. Free and cross-platform.
Best for: a simple, familiar way to browse a broker. See the MQTT Explorer alternative page.
MQTTX (the all-in-one toolkit)
From the team behind EMQX, MQTTX spans a desktop app, a web client and a CLI, with benchmarking and a broad set of payload codecs.
Best for: one toolset covering GUI, CLI and browser. See the MQTTX alternative page.
MQTT.fx (the polished commercial option)
MQTT.fx 5.x from Softblade is a commercial desktop client with a Topic Explorer, Sparkplug tooling and vendor support, under paid licences.
Best for: teams that want vendor support. See the MQTT.fx alternative page.
HiveMQ web client (nothing to install)
A free, browser-based MQTT client over WebSocket. Nothing to install.
Best for: a quick connection test from any machine.
How to choose
MQTT Viewer for a free desktop app focused on debugging traffic. MQTTX for an all-in-one toolkit with a CLI. MQTT Explorer for a familiar single-broker tree. MQTT.fx for commercial support. The HiveMQ web client for something in the browser.
Frequently asked questions
What is the best free MQTT client?
MQTT Viewer is a free, open-source desktop client focused on debugging traffic. MQTTX is a free, all-in-one toolkit with a CLI and web client. MQTT Explorer is a free single-broker topic-tree browser.
Which MQTT clients are free and open source?
MQTT Viewer is free and open-source under GPL-3.0, and MQTTX is free and open-source under Apache-2.0. MQTT Explorer is free and cross-platform as well.
What's a good MQTT client for Mac, Windows, and Linux?
MQTT Viewer is a free, open-source native desktop app for macOS, Windows and Linux.
MQTT Viewer is free and open source, and runs on macOS, Windows and Linux.
Download MQTT Viewer