> For the complete documentation index, see [llms.txt](https://freegrow-1.gitbook.io/product-docs-en/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://freegrow-1.gitbook.io/product-docs-en/en-creator-kit-q1/uwb-creator-kit-q1-complete-setup-and-usage-guide/advanced-guide-for-gateway/mqtt-data-format.md).
# MQTT Data Format
### In This Guide
In this guide, we provide a detailed overview of the types and formats of data received through **MQTT-Studio**, helping you effectively check device status and integrate with the location system.
***
### How to Check MQTT Data
The data sent from the gateway can be viewed through the **Topic** subscribed in **MQTT-Studio**.
* Example of a Topic:
* `uwb/gateway/start/#`
* `uwb/gateway/config/#`
* `uwb/gateway/devices/#`
Click on the message in **MQTT-Studio** to view the detailed JSON data.\
You can also click the **copy** button on the right to copy the data as text for easy analysis in a text editor such as Notepad.
***
### Examples and Descriptions of Data Types
The main types of data sent from the **GrowSpace Gateway** are categorized into the following four types:
***
#### Start Data
* **Transmission Time**: Sent once immediately after the gateway boots up
* **Purpose**: To verify device boot and network connection status
Once the gateway receives power and boots up properly, it sends a **`start`** message to indicate the system's initial state.\
This message allows you to verify the **gateway device ID**, **Pan ID**, and **current IP address**.
```json
{
"uwbID": "GR21BA",
"panID": "0001",
"ip": "172.30.1.177"
}
```
Use Cases**:**
* When verifying if the gateway is properly connected to the network
* To identify the device and check its installation location
***
#### Config Data
* **Transmission Time**: Repeatedly sent at regular intervals
* **Purpose**: Device heartbeat signal
The **config** data is periodically transmitted to indicate that the gateway is still operational.\
The format is the same as the **start** data, but it is used for continuous heartbeat signaling.
```json
{
"uwbID": "GR21BA",
"panID": "0001",
"ip": "172.30.1.177"
}
```
Use Cases**:**
* To check the **online status** of the system
* To detect **device failures** or **network disconnections**
***
#### Anchor Information (devices – anchors)
* **Transmission Time**: When the gateway recognizes an anchor
* **Purpose**: To transmit the location and role of the anchor
This message includes the **UWB anchor’s ID**, **coordinates**, **Pan ID**, and whether it is the **initiator**.
This information is used to configure the anchor data, which serves as the reference for location calculation.
```json
{
"gatewayID": "GR21BA",
"anchors": [
{
"id": "GR365d",
"panID": "0001",
"initiator": true,
"x": -2.92,
"y": 0.35,
"z": 0.00
}
]
}
```
Use Cases**:**
* Automating the registration of anchor locations
* Mapping reference points when configuring the system’s map
***
#### Tag Location Information (devices – tags)
* **Transmission Time**: Sent repeatedly each time the location calculation is completed
* **Purpose**: Real-time location tracking
The gateway calculates the current position coordinates (x, y, z) of UWB tags and sends them as a single message.\
Multiple tags may be included in one message, which is composed of the **`gateway ID`**, **`Pan ID`**, **`tag ID`**, and **`coordinates`**.
```json
{
"gatewayID": "GR21BA",
"tags": [
{"id":"GR2c3c", "panID":"0001", "x": -3.95, "y": 0.23, "z": -2.48},
{"id":"GR1012", "panID":"0001", "x": -1.48, "y": 3.42, "z": 0.66},
{"id":"GR2eba", "panID":"0001", "x": -4.27, "y": 0.20, "z": -2.36}
]
}
```
Use Cases**:**
* Integration with a **real-time location visualization dashboard**
* **Tag movement path analysis**
* Setting up **geofencing** for use cases like **entrance detection**, **hazard zone intrusion alerts**, etc.
***
### Summary and Tips
| Data Types | MQTT Topic | Transmission Purposes |
| ---------- | ----------------------- | ---------------------------------------------------- |
| Start | `uwb/gateway/start/#` | Gateway boot status verification |
| Config | `uwb/gateway/config/#` | **Device operation status check** (heartbeat signal) |
| Anchors | `uwb/gateway/devices/#` | **Anchor information** provided |
| Tags | `uwb/gateway/devices/#` | Tag location data transmission |
* The **`projectId`** within the Topic is configured based on the **API key**, and it will appear differently for each system.
* For real-time debugging or system verification, check the flow of **Start → Config → Devices** to ensure proper data reception.