# Things

A Thing is an individual device identity registered in EMQX Fleets. Each Thing has a name and an MQTT Client ID, and can optionally be associated with a Thing Type that defines its schema.

## Register a Thing

1. In your Fleets deployment, go to **Device Management** > **Things**.
2. Click **+ Register Thing**.
3. Fill in the fields:
   - **Name** (required): A unique identifier for this device within the deployment. Used as `{thingName}` in MQTT topics and API calls.
   - **MQTT Client ID** (required): The MQTT `CONNECT` packet Client ID this device will use. Must match the Client ID the physical device sends when connecting to EMQX Broker.
   - **Thing Type** (optional): Associate this device with a Thing Type to inherit its schema.
   - **Group** (optional): Assign the device to a Thing Group.
   - **Tags** (optional): Tags to associate with this device.
4. Click **Confirm**.

![register_thing](./_assets/register_thing.png)

The Thing is created with an **offline** status. It becomes **online** when a device connects to EMQX Broker using the configured MQTT Client ID.

## Thing Identity Fields

Each Thing has three identity fields that serve different purposes:

| Field | Used for |
|---|---|
| **Thing ID** | System-generated UUID; used internally and in API path parameters |
| **Name** | `{thingName}` in all `$emqx/things/{thingName}/...` MQTT topics and in API request bodies |
| **MQTT Client ID** | The MQTT `CONNECT` packet Client ID; used for connection lifecycle tracking (online/offline status) |

Name and MQTT Client ID may be the same, but they are independent. For example, a Thing named `sensor-001` might connect with MQTT Client ID `sensor-001`.

## Thing Status

| Status | Meaning |
|---|---|
| **online** | The device is currently connected to EMQX Broker |
| **offline** | The device is not currently connected |

Status is updated automatically based on MQTT connect and disconnect events.

## View Thing Details

Click a Thing name in the list to open its detail page. The top of the page shows four summary cards:

- **Status**: Current connection status and last online time.
- **Thing Type**: The associated Thing Type name and ID.
- **Schema**: Count of properties, events, and commands inherited from the Thing Type, shown as `properties / events / commands`.
- **Relationships**: Count of tags and Thing Groups, shown as `tags / groups`.

![view_thing_details](./_assets/view_thing_details.png)

The detail page has the following tabs:

### Details

Shows the Thing's identity and timestamp fields:

| Field | Description |
|---|---|
| Thing ID | System-generated unique identifier |
| MQTT Client ID | The MQTT Client ID configured at registration |
| Status | Current connection status |
| Updated At | When the Thing record was last updated |
| Last Offline | When the device last disconnected |
| Name | The Thing name |
| Thing Type | The associated Thing Type |
| Created At | When the Thing was registered |
| Last Online | When the device last connected |

### Properties

Lists the properties defined in the Thing Type schema, with the following columns:

| Column | Description |
|---|---|
| Name | Property name |
| Type | Data type (`string`, `int`, `float`, `boolean`, or `enum`) |
| Details | Writable status, unit, and value range (where applicable) |
| Description | Property description |

![thing_details_properties](./_assets/thing_details_properties.png)

### Events

Lists the events defined in the Thing Type schema, with the following columns:

| Column | Description |
|---|---|
| Name | Event name |
| Severity | `info`, `warn`, or `error` |
| Description | Event description |

![thing_details_events](./_assets/thing_details_events.png)

### Commands

Lists the commands defined in the Thing Type schema. Click **+ Send Command** to send a command to this device directly from the detail page.

| Column | Description |
|---|---|
| Name | Command name |
| Type | Command type (`sync`) |
| Details | Input parameters, output parameters, and timeout |
| Description | Command description |

![thing_details_commands](./_assets/thing_details_commands.png)

### Relationships

Shows the Thing Groups the device belongs to and the tags assigned to it:

- **Thing Groups**: A table listing the groups by Name and Description.
- **Tags**: Tags displayed as chips.

![thing_details_relationships](./_assets/thing_details_relationships.png)

### Jobs

Lists job executions targeting this device. Use the **Status** filter to narrow the list.

| Column | Description |
|---|---|
| Job ID | Links to the job execution detail |
| Attempt | Number of execution attempts |
| Status | Current execution status |
| Shadow Version | Shadow version at the time of execution |
| Error Message | Error detail if the execution failed |
| Updated At | When the execution was last updated |

![thing_details_jobs](./_assets/thing_details_jobs.png)

## Export and Import Things

To export Things as a JSON file, select one or more Things using the checkboxes, then click **Export**.

To import Things from a JSON file, click **Import**, then select the file.

## Edit a Thing

1. In the **Things** list, click the edit icon in the **Actions** column.
2. Update the fields:
   - **Name** (required)
   - **MQTT Client ID** (required)
   - **Thing Type** (optional)
   - **Group** (optional): **Group Tags** displays the tags of the selected group and is read-only.
   - **Tags** (optional)
3. Click **Confirm**.

## Filter and Search

The Things list supports filtering by:

- **Thing Type**: Show only Things of a specific type.
- **Group**: Show only Things that are members of a specific Thing Group.
- **Tags**: Show only Things with specific tags.
- **Status**: Filter by `online` or `offline`.

Use the search icon to search by Thing name.

## Delete a Thing

1. In the **Things** list, click the delete icon in the **Actions** column.
2. Confirm the deletion.

Deleting a Thing removes its registration, shadow state, and group memberships.

## Next Steps

- [Thing Groups](./thing_groups.md)
- [Device Shadow](../device_shadow.md)
- [Device Query](../device_query.md)
- [Connect a Device via MQTT](../device_integration/mqtt_integration.md)