# Session object

A session is the link between your application and a headset.

You must create a session before you call [subscribe](https://emotiv.gitbook.io/cortex-api/data-subscription/subscribe) to receive data from a headset. See [createSession](https://emotiv.gitbook.io/cortex-api/session/createsession).

## Description

A session object includes these fields:

| Name      | Type                    | Description                                                                                                                                        |
| --------- | ----------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
| id        | `string`                | The id of this session.                                                                                                                            |
| status    | `string`                | Can be "opened", "activated", or "closed".                                                                                                         |
| owner     | `string`                | The EmotivID of the user.                                                                                                                          |
| license   | `string`                | The id of the license used by this session. Or an empty string if the session wasn't activated.                                                    |
| appId     | `string`                | The application id of your Cortex app.                                                                                                             |
| started   | `string (ISO datetime)` | When this session was created.                                                                                                                     |
| stopped   | `string (ISO datetime)` | When this session was closed.                                                                                                                      |
| streams   | `array of strings`      | The data streams you subscribed to. See [subscribe](https://emotiv.gitbook.io/cortex-api/data-subscription/subscribe).                             |
| recordIds | `array of strings`      | The ids of all the records created by this session. See [createRecord](https://emotiv.gitbook.io/cortex-api/records/createrecord).                 |
| recording | `boolean`               | True if a record is currently in progress for this session. False otherwise.                                                                       |
| headset   | `object`                | A [headset object](https://emotiv.gitbook.io/cortex-api/headset/headset-object). It contains information about the headset linked to this session. |

### Status

The status is linked to the license. If the session is activated, it will be debited from the quota of the user's license.

| Status    | Description                                                                                                                                                                                                                                                      |
| --------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| opened    | The session was created with [createSession](https://emotiv.gitbook.io/cortex-api/session/createsession), but it doesn't use a license. You can activate or close this session with [updateSession](https://emotiv.gitbook.io/cortex-api/session/updatesession). |
| activated | The session was activated with a license. You can close this session with [updateSession](https://emotiv.gitbook.io/cortex-api/session/updatesession).                                                                                                           |
| closed    | This session is closed, you cannot use it anymore.                                                                                                                                                                                                               |

## Examples

A session with an Epoc+ headset. It is not activated. We subscribed to the performance metrics and motion data.

```javascript
{
    "id": "8bfc26de-754b-4c1f-9771-acfd1a7da02c",
    "status": "opened",
    "owner": "jon.snow",
    "license": "",
    "appId": "com.jon.snow.winterfell-app",
    "started": "2019-05-29T14:18:45.108+07:00",
    "stopped": "",
    "headset": {
        "status": "connected"
        "connectedBy": "dongle",
        "customName": "",
        "dongle": "6ff",
        "firmware": "625",
        "id": "EPOCPLUS-3B9AXXXX",
        "motionSensors": [
            "GYROX",
            "GYROY",
            "GYROZ",
            "ACCX",
            "ACCY",
            "ACCZ",
            "MAGX",
            "MAGY",
            "MAGZ"
        ],
        "sensors": [
            "AF3",
            "F7",
            "F3",
            "FC5",
            "T7",
            "P7",
            "O1",
            "O2",
            "P8",
            "T8",
            "FC6",
            "F4",
            "F8",
            "AF4"
        ],
        "settings": {
            "eegRate": 256,
            "eegRes": 16,
            "memsRate": 64,
            "memsRes": 16,
            "mode": "EPOCPLUS"
        }
    },
    "recordIds": [],
    "recording": false,
    "streams": ["met","mot"]
}
```