MQTT message diff

The compare tab diffs the selected message against the previous one on the same topic and highlights the lines that changed.

How the diff works

The diff is line-based over the formatted payload, so JSON diffs field by field. Step through history on the timeline and the comparison follows.

Can MQTT Viewer diff two arbitrary messages?

The diff always compares the selected message with the one before it on the same topic. Step back through the timeline to move the pair.

Does the diff work on binary payloads?

The diff runs over the formatted payload, so a Sparkplug B, Base64 or Hex payload is decoded first and the decoded JSON is compared.

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