---
title: Testing an MQTT connection
slug: how-tos/9wwo-testing-an-mqtt-connection
docTags: NdAmj9E8yTRkwQ9gl8SF9
createdAt: 2025-09-19T13:27:11.372Z
---

This guide shows how to **connect and read** data with **MQTT Explorer** for **both** MQTT collector types in Factry Historian:

- **MQTT (Generic)**: free-form topics with JSON payloads
- **MQTT (Sparkplug B)**: Sparkplug v1.0 topics/payloads

The goal: **see paths/topics and payloads arriving**. We won’t publish anything.

Example broker uses **unencrypted TCP**: *tcp\://mqtt.realfakedata.com:1883*. In production, use **TLS** (e.g., ssl://host:8883) with authentication.

## Prerequisites

- **[MQTT Explorer](https://mqtt-explorer.com/)** installed (Windows/macOS/Linux)
- Network access to *mqtt.realfakedata.com:1883*

## Steps

1. **Add new connection** in MQTT Explorer
   - Host: mqtt.realfakedata.com
   - Port: 1883
   - Protocol: MQTT/TCP (no TLS)
2. In **Advanced → Topic**, add an initial topic (see below per collector).
3. **Connect** and watch the left **topic tree**; click nodes to inspect payloads on the right.
4. Note the **exact topic paths** and **payload fields** you’ll use when configuring Historian.

![](https://api.archbee.com/api/optimize/SMPo4IS9FkillUAMsur2c/C1FGIIkt2I5bcwSdqNIRm_image.png)

## MQTT (Generic)

### Subscribe filters

Start broad to discover, then narrow:

- Discovery: # *(briefly, for exploration only)*
- Typical: factry/demo/#
- Narrow: factory/line-1/mixer-01/metrics

**Wildcards**

- `+` = one level (factory/+/metrics)
- `#` = multi-level, last (factory/#)

![](https://api.archbee.com/api/optimize/SMPo4IS9FkillUAMsur2c/Z6a-liQqjZhESe9Tiprg2_image.png)

### What to look for

- **Topic paths** under your filter
- **Payload format**: usually JSON
  - value fields (e.g., temperature, pressure)
  - timestamp field (e.g., ts)
  - quality/status (e.g., status)
  - identifiers/tags (e.g., machineId, line)

**Example payload you might see**

:::BlockQuote
\{
  "temperature": 23.5,
  "status": "Good",
  "ts": "2025-09-18T09:45:00Z",
  "machineId": "Mixer-01"
}
:::

### Map to Historian (Generic)

- **Collector**
  - **MqttURL:** tcp\://mqtt.realfakedata.com:1883
  - **Topics:** the filter you confirmed (e.g., factry/demo/#)
  - **QoS:** 1 (recommended)
  - **TimestampLayout (default):** RFC3339 *(or UNIX/UNIXMILLIS/UNIXMICROS/UNIXNANOS)*
- **Measurement (per datapoint)**
  - **MeasurementPath:** $.temperature
  - **TimestampPath:** $.ts
  - **TimestampLayout:** RFC3339
  - **StatusPath:** $.status
  - **TagNamesAndTagValuePaths:** \{"machine":"$.machineId"}

If **TimestampPath**/**TimestampLayout** are omitted on the measurement, the **collector’s** TimestampLayout is used.

## MQTT (Sparkplug B)

### Subscribe filters (Sparkplug v1.0)

Sparkplug topic schema: `spBv1.0/<group>/<message_type>/<edgeNode>[/<device>]`
` <message_type>` ∈ `NBIRTH, NDEATH, DBIRTH, DDEATH, NDATA, DDATA, NCMD, DCMD`

Start with one of:

- Discovery (group): `spBv1.0/<group>/#`
- All node data for an edge node: `spBv1.0/<group>/NDATA/<edgeNode>/#`
- All device data under an edge node: `spBv1.0/<group>/DDATA/<edgeNode>/+`

### What to look for

- **Birth messages** (NBIRTH/DBIRTH): inventory of metrics and initial state
- **Data messages** (NDATA/DDATA): live metric updates
- **Payload**: binary

### Map to Historian (Sparkplug B)

- **Collector**
  - **MqttURL:** tcp\://mqtt.realfakedata.com:1883
  - **Topics:** your confirmed Sparkplug filter (e.g., spBv1.0/\<group>/NDATA/\<edgeNode>/#)
  - **TimestampLayout (default):** set per your publisher (e.g., UNIXMILLIS)
- **Measurement (per metric)**
  - **GroupID**: \<group>
  - **EdgeNodeID**: \<edgeNode>
  - **DeviceID**: \<device> *(if applicable)*
  - **MetricName**: e.g., Temperature

## Troubleshooting

- **Connected, no data:** widen your filter (# briefly to discover), then narrow again. Some topics only update periodically.
- **Too much noise:** tighten the filter (e.g., factry/demo/hello or spBv1.0/\<group>/NDATA/\<edgeNode>/+).
- **Connection blocked:** ensure mqtt.realfakedata.com:1883 is reachable (firewall/VPN/proxy).

Once you can **see the paths and payloads** in MQTT Explorer, copy those **exact** topics and JSON fields into your Historian collector/measurement settings.