---
title: MQTT Explorer
description: Browse the Edge Server\
source: https://documentation.controlcomtech.com/build/edge-server/web-interface/tools/mqtt-explorer
---

# MQTT Explorer

`/tools/mqtt-explorer` connects directly to the Edge Server's embedded Sparkplug B broker over MQTT-over-WebSockets and gives you a live, browsable view of the topic tree.

> **Workflow Stage: Collect**

**Connection**

| Field    | Default     | Notes                                           |
| -------- | ----------- | ----------------------------------------------- |
| **Host** | page origin | Defaults to the host the UI is loaded from.     |
| **Port** | page port   | Same as the UI port (typically 3041).           |
| **Path** | `/mqtt`     | The broker is co-hosted with the UI at `/mqtt`. |

Click **Connect** to open the session; the status badge cycles through Connecting → Connected (or Error). **Disconnect** closes it.

**Topic tree**

The left panel shows a collapsible Sparkplug B hierarchy (group → edge node → device → metric). Each branch displays a message-count badge. Selecting a topic opens the detail view on the right.

**Payload detail**

* Latest message metadata (topic, timestamp, size).
* A decoded Sparkplug B metrics table with **Name**, **Type**, **Value**, and **Timestamp**.
* History picker for navigating older messages on the same topic (capped per topic to keep memory predictable).

**Controls**

* **Pause**: freezes incoming traffic. New messages are dropped while paused and a counter shows how many were missed.
* **Clear**: wipes the topic tree without disconnecting.
* **Send Command**: only enabled on Sparkplug B topics; opens the NCMD/DCMD composer.

**Send Command dialog**

* **NCMD** actions: **Rebirth** (force the edge node to republish its DBIRTH) and **Reboot**.
* **DCMD** writes to a specific metric: pick the metric (from the most recent DBIRTH), choose its datatype, and supply a value. Boolean metrics get a switch; numeric metrics get an input.
* The dialog shows the metric's current value and flashes when a new DDATA arrives, giving you immediate confirmation that your command landed.

> The Sparkplug B broker requires admin authentication. The Explorer uses the same JWT issued at sign-in, so there is no separate credential to enter.