# Get Registered Callback Listeners ### `GET /callbacks/{accountName}` Returns the endpoint URL of the callback listening service registered for a given account. ## HTTP Request [GET https://thingspace.verizon.com/api/fota/v3/callbacks/{accountName}](/docs/standard-apis/connectivity-management/api-endpoints/connectivity-callbacks/list-registered-callbacks/listregisteredcallbacks) ## Header Parameters The request header must contain a current ThingSpace authorization token, set the content to "JSON" and a current VZ-M2M-session token. |Parameter Name|Data Type|Description| |-----|-----|-----| | **Authorization** *(required)* | string | HTTP Authorization request header containing a valid Bearer token: `Authorization: Bearer {token}` | | **VZ-M2M-Token** *(required)* | string | A valid session token returned by a Connectivity Management `POST /session/login` request. | | **Content-Type** *(required)* | string | Must be `application/json`. | ## Request Parameters The `accountName` must be included in the path. |Parameter Name|Data Type|Description| | **accountName** *(required)* | string | The name of the account for which a list of registered callback services will be returned. An account name is numeric, and must include any leading zeros. | ## Request Body None. ## Success Response **Status 200** Example Response: ```json { "url": "http://10.120.102.183:50559/CallbackListener/FirmwareServiceMessages.asmx" } ``` ## Success Parameters |Parameter Name|Data Type|Description| |-----|-----|-----| | **url** | string | The address of the callback listening service where ThingSpace sends callback messages for the service type. | **Note:** The response body will be empty if there are no callback services registered with the account. ## Failure Responses All error messages are returned in this format: ```json { "errorCode": "error code string", "errorMessage": "error message string" } ``` Error codes and messages are listed on the [Error Messages page](https://thingspace.verizon.com/documentation/api-documentation.html#/http/software-management/guides/error-messages), along with explanations and suggestions for corrective actions.