### Client Parameters
- **client_id**  
   The unique ID associated with your developer project.

- **geofence_id**  
   The unique ID associated with the user-created geofence. A Geofence ID is generated for all geofences and can be found in your Developer Console.

- **oauth_token**  
   The access token generated via your web application as described [here](https://docs.foursquare.com/developer/reference/v2-authentication).

- **name**  
   A custom string that you can set to help you identify the set of geofences.

- **venueId**  
   A single Foursquare `venueId`.

- **categoryId**  
   A single Foursquare category.

- **chainId**  
   A single Foursquare chain.

- **center**  
   A comma separated lat/long coordinate.

- **radius**  
   Area around the lat/lng that will trigger a geofence event. Default and minimum radius is 50 meters, with a max of 5000.

- **dwellTime**  
   Number of minutes user needs to be inside of a geofence to trigger a dwell event. Default is 1 minute.

- **v**  
   The API version date as documented [here](https://developer.foursquare.com/reference/versioning).

- **properties**  
   A string of comma-separated key-value pairs containing metadata about the venue associated with the geofence. Can contain up to 10 key-value pairs formatted as `museum_type=Art,has_cafe=yes`.

### Response Example
#### Success (200)
```json
{
  "meta": {
    "code": 200,
    "requestId": "5cab901e4c1f6715dfb6dee7"
  },
  "notifications": [
    {
      "type": "notificationTray",
      "item": {
        "unreadCount": 0
      }
    }
  ],
  "response": {
    "geofence": {
      "type": "LatLng",
      "name": "My Custom Location",
      "id": "5cab901ebfc6d0002ce1ff33",
      "boundary": {
        "center": {
          "lat": 40.7435179,
          "lng": -73.988242149
        },
        "radius": 100
      },
      "dwellTime": 2
    }
  }
}
```

#### Error (400)
```json
{
  "meta": {
    "code": 400,
    "requestId": "Error_Request_ID"
  },
  "notifications": [],
  "response": {}
}
```

### cURL Example
```bash
curl --request POST \
     --url https://api.foursquare.com/v2/apps/client_id/geofence/geofence_id/update \
     --header 'accept: application/json'
```