The response is a JSON object with the following properties

+----------------+-----------+------------------------------------------------------------------------+
| Property       | Type      | Description                                                            |
+================+===========+========================================================================+
| *time*         | integer   | The time which the state vectors in this response are associated with. |
|                |           | All vectors represent the state of a vehicle with the interval         |
|                |           | :math:`[time - 1, time]`.                                              |
+----------------+-----------+------------------------------------------------------------------------+
| *states*       | array     | The state vectors.                                                     |
+----------------+-----------+------------------------------------------------------------------------+

The *states* property is a two-dimensional array. Each row represents a :ref:`state vector <state-vectors>`
and contains the following fields:

+-------+-------------------+---------+------------------------------------------------------------------+
| Index | Property          | Type    | Description                                                      |
+=======+===================+=========+==================================================================+
| 0     | *icao24*          | string  | Unique ICAO 24-bit address of the transponder in hex string      |
|       |                   |         | representation.                                                  |
+-------+-------------------+---------+------------------------------------------------------------------+
| 1     | *callsign*        | string  | Callsign of the vehicle (8 chars). Can be null if no callsign    |
|       |                   |         | has been received.                                               |
+-------+-------------------+---------+------------------------------------------------------------------+
| 2     | *origin_country*  | string  | Country name inferred from the ICAO 24-bit address.              |
+-------+-------------------+---------+------------------------------------------------------------------+
| 3     | *time_position*   | int     | Unix timestamp (seconds) for the last position update. Can be    |
|       |                   |         | null if no position report was received by OpenSky within the    |
|       |                   |         | past 15s.                                                        |
+-------+-------------------+---------+------------------------------------------------------------------+
| 4     | *last_contact*    | int     | Unix timestamp (seconds) for the last update in general. This    |
|       |                   |         | field is updated for any new, valid message received from the    |
|       |                   |         | transponder.                                                     |
+-------+-------------------+---------+------------------------------------------------------------------+
| 5     | *longitude*       | float   | WGS-84 longitude in decimal degrees. Can be null.                |
+-------+-------------------+---------+------------------------------------------------------------------+
| 6     | *latitude*        | float   | WGS-84 latitude in decimal degrees. Can be null.                 |
+-------+-------------------+---------+------------------------------------------------------------------+
| 7     | *baro_altitude*   | float   | Barometric altitude in meters. Can be null.                      |
+-------+-------------------+---------+------------------------------------------------------------------+
| 8     | *on_ground*       | boolean | Boolean value which indicates if the position was retrieved from |
|       |                   |         | a surface position report.                                       |
+-------+-------------------+---------+------------------------------------------------------------------+
| 9     | *velocity*        | float   | Velocity over ground in m/s. Can be null.                        |
+-------+-------------------+---------+------------------------------------------------------------------+
| 10    | *true_track*      | float   | True track in decimal degrees clockwise from north (north=0°).   |
|       |                   |         | Can be null.                                                     |
+-------+-------------------+---------+------------------------------------------------------------------+
| 11    | *vertical_rate*   | float   | Vertical rate in m/s. A positive value indicates that the        |
|       |                   |         | airplane is climbing, a negative value indicates that it         |
|       |                   |         | descends. Can be null.                                           |
+-------+-------------------+---------+------------------------------------------------------------------+
| 12    | *sensors*         | int[]   | IDs of the receivers which contributed to this state vector.     |
|       |                   |         | Is null if no filtering for sensor was used in the request.      |
+-------+-------------------+---------+------------------------------------------------------------------+
| 13    | *geo_altitude*    | float   | Geometric altitude in meters. Can be null.                       |
+-------+-------------------+---------+------------------------------------------------------------------+
| 14    | *squawk*          | string  | The transponder code aka Squawk. Can be null.                    |
+-------+-------------------+---------+------------------------------------------------------------------+
| 15    | *spi*             | boolean | Whether flight status indicates special purpose indicator.       |
+-------+-------------------+---------+------------------------------------------------------------------+
| 16    | *position_source* | int     | Origin of this state's position.                                 |
|       |                   |         |                                                                  |
|       |                   |         | * 0 = ADS-B                                                      |
|       |                   |         | * 1 = ASTERIX                                                    |
|       |                   |         | * 2 = MLAT                                                       |
|       |                   |         | * 3 = FLARM                                                      |
+-------+-------------------+---------+------------------------------------------------------------------+
| 17    | *category*        | int     | Aircraft category.                                               |
|       |                   |         |                                                                  |
|       |                   |         | * 0 = No information at all                                      |
|       |                   |         | * 1 = No ADS-B Emitter Category Information                      |
|       |                   |         | * 2 = Light (< 15500 lbs)                                        |
|       |                   |         | * 3 = Small (15500 to 75000 lbs)                                 |
|       |                   |         | * 4 = Large (75000 to 300000 lbs)                                |
|       |                   |         | * 5 = High Vortex Large (aircraft such as B-757)                 |
|       |                   |         | * 6 = Heavy (> 300000 lbs)                                       |
|       |                   |         | * 7 = High Performance (> 5g acceleration and 400 kts)           |
|       |                   |         | * 8 = Rotorcraft                                                 |
|       |                   |         | * 9 = Glider / sailplane                                         |
|       |                   |         | * 10 = Lighter-than-air                                          |
|       |                   |         | * 11 = Parachutist / Skydiver                                    |
|       |                   |         | * 12 = Ultralight / hang-glider / paraglider                     |
|       |                   |         | * 13 = Reserved                                                  |
|       |                   |         | * 14 = Unmanned Aerial Vehicle                                   |
|       |                   |         | * 15 = Space / Trans-atmospheric vehicle                         |
|       |                   |         | * 16 = Surface Vehicle – Emergency Vehicle                       |
|       |                   |         | * 17 = Surface Vehicle – Service Vehicle                         |
|       |                   |         | * 18 = Point Obstacle (includes tethered balloons)               |
|       |                   |         | * 19 = Cluster Obstacle                                          |
|       |                   |         | * 20 = Line Obstacle                                             |
+-------+-------------------+---------+------------------------------------------------------------------+