A lightweight, focused MQTTX alternative

MQTTX is a powerful, well-rounded MQTT toolkit. If you mainly want a fast, focused desktop app for seeing and debugging what's on your broker, MQTT Viewer is a lighter, topic-tree-first alternative — free and open-source.

What MQTTX does well

MQTTX, from the team behind the EMQX broker, is a genuinely capable, actively developed toolkit. It spans a desktop app, a web client, and a command-line tool, supports full MQTT 5.0, includes benchmarking, and decodes a wide range of payload formats. If you want one all-in-one toolset — especially with a CLI for scripting and automation or a browser-based client — MQTTX is an excellent choice.

Where MQTT Viewer fits

MQTT Viewer is deliberately narrower. It's a single, fast, native desktop app focused on one job: helping you see and understand what's flowing through a broker. That focus shows up as:

  • Topic-tree-first. The hierarchical topic tree is the centre of the interface, paired with an interactive timeline and message comparison.
  • Lightweight and native. One native app (Go + Svelte + Wails) for macOS, Windows, and Linux that installs in seconds and starts fast.
  • Broker-neutral. MQTT Viewer isn't tied to any broker — point it at Mosquitto, EMQX, HiveMQ, or anything else.
  • The essentials, done well. Up to 10 connections, full MQTT v3.1.1 and v5, TLS/mTLS/WebSocket, Sparkplug B / Base64 / Hex decoding, and a searchable publish history.
  • Free and open-source under GPL-3.0, with no account.

Which one is right for you?

If you want a broad toolkit with a CLI, a web client, and benchmarking, MQTTX is a great fit. If you want a small, fast, broker-neutral desktop app that's mostly about visualizing and debugging live traffic, MQTT Viewer is the leaner option — and it's free to try in seconds.

Frequently asked questions

Is MQTT Viewer a lightweight alternative to MQTTX?

Yes. MQTT Viewer is a focused, native desktop client built around a live topic tree for seeing and debugging broker traffic. It's free and open-source, with no account required.

Does MQTT Viewer support MQTT 5 and multiple connections?

Yes. MQTT Viewer supports full MQTT v3.1.1 and v5 and up to 10 simultaneous broker connections, the everyday essentials for debugging.

Is MQTT Viewer tied to a particular broker?

No. MQTT Viewer is broker-neutral and works with any MQTT broker, including Mosquitto, EMQX, HiveMQ, and others.

Does MQTT Viewer decode binary payloads?

Yes. MQTT Viewer decodes Sparkplug B (protobuf), Base64, and Hex payloads, and offers free-text and pattern-based filtering.

Want the bigger picture? See the best MQTT clients overview, or download MQTT Viewer for macOS, Windows, or Linux.

MQTT Viewer is free, open-source, and runs on macOS, Windows & Linux.

Download MQTT Viewer