> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chargeapi.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Expanding Responses

Many Charge objects allow related resources to be expanded inline by using the `expand` query parameter.

<Panel>
  <RequestExample>
    ```bash cURL theme={null}
    curl -G https://api.chargeapi.co/v1/reservations/res_nfJiRR1ok35nSfnIpS4tC7SAsUk0K3As \
      -H "Authorization: Bearer ch_sk_test_..." \
      -d expand=driver \
      -d expand=vehicle.fleet
    ```
  </RequestExample>

  <ResponseExample>
    ```json Response theme={null}
    {
        "id": "res_nfJiRR1ok35nSfnIpS4tC7SAsUk0K3As",
        "object": "reservation",
        "charging_station": "chst_AwAMEuLnH0Umz3DhtEjEaHACtMcscDDY",
        "driver": {
            "id": "drv_OAVzBPkaauGK3svjp2YxHyGkZxPjIuSB",
            "object": "driver"
            // ...
        },
        "payment_method": "pm_ifwG4OMNnEmqjpi7cP8EJvxiRZAzGOEX",
        "status": "confirmed",
        "vehicle": {
            "id": "veh_O3C7oq0HKOkNlpzokFN5eTTVWImdeLKy",
            "object": "vehicle",
            "fleet": {
                "id": "flt_nnMosKd4naheDFTiLmLhZ3Yw64xg9enI",
                "object": "fleet"
                // ...
            }
            // ...
        }
        // ...
    }
    ```
  </ResponseExample>
</Panel>

By default, expandable fields are returned as IDs. Adding `expand` tells Charge to replace those IDs with full objects in the same response, which is useful when you already know which related records your client needs.

To expand more than one relation, repeat `expand` once per path. That can include nested paths such as `vehicle.fleet` when that relation chain is supported. The exact values you can use depend on the object returned by that endpoint, and they are listed on the relevant object pages and endpoint references. If you send a path that is not supported, Charge returns `unsupported_expand_value`.

<Tip>Use `expand`, not `expand[]`.</Tip>

## Where expansion is available

| Returned object                                                | Allowed `expand` values                                            |
| -------------------------------------------------------------- | ------------------------------------------------------------------ |
| [Account](/api-reference/accounts/object)                      | `preferences.default_payment_method`                               |
| [Charging Session](/api-reference/charging_sessions/object)    | `charging_station`, `driver`, `fleet`, `payment_method`, `vehicle` |
| [Driver](/api-reference/drivers/object)                        | `preferences.default_payment_method`                               |
| [Estimation](/api-reference/estimations/object)                | `charging_station`, `vehicle`                                      |
| [Fleet](/api-reference/fleets/object)                          | `preferences.default_payment_method`                               |
| [Payment Method](/api-reference/payment_methods/object)        | `driver`, `fleet`                                                  |
| [Report](/api-reference/reports/object)                        | `account`, `fleet`                                                 |
| [Reservation](/api-reference/reservations/object)              | `charging_station`, `driver`, `payment_method`, `vehicle`          |
| [Transaction](/api-reference/transactions/object)              | `charging_session`, `driver`, `payment_method`, `vehicle`          |
| [Vehicle](/api-reference/vehicles/object)                      | `fleet`, `telemetry`                                               |
| [Vehicle Telemetry](/api-reference/vehicle_telemetries/object) | `vehicle`                                                          |