API Method: `POST /settings/changeDefaultTransfersFinAccount`

Description:

This endpoint updates the default financial account used for Account-to-Account (A2A) transfers in the banking application. It allows the authenticated user to change which financial account is set as the default for initiating A2A transfers, either between internal accounts or to external accounts.

Request:

HTTP Method: POST
Endpoint: /settings/changeDefaultTransfersFinAccount
Authentication: Requires authentication (e.g., Bearer token or session ID) to ensure only authorized users can change the default financial account for A2A transfers.

Request Body:

Content-Type: application/json

Request Fields:

accountId (string, required): The unique identifier for the financial account to be set as the new default for A2A transfers.
accountType (string, required): The type of account, such as checking, savings, or investment.
isExternalAccount (boolean, required): Indicates whether the new default account is external (true) or internal (false) to the bank.
bankName (string, optional): The name of the financial institution where the new account is held, required only if it is an external account.
routingNumber (string, optional): The routing number of the financial institution for the new account, typically required if the account is external to the bank.

Response:

Status Code: 200 OK — On success, the API confirms that the default financial account for A2A transfers has been successfully updated.
Content-Type: application/json

Possible Errors:

400 Bad Request: The request contains invalid parameters, such as missing or incorrectly formatted data.
401 Unauthorized: The request was made without valid authentication or with an invalid token.
403 Forbidden: The user does not have permission to update the default financial account.
404 Not Found: The specified account could not be found or is invalid.
500 Internal Server Error: An error occurred on the server while processing the request.

This request updates the user's default financial account for A2A transfers to a new account by specifying the account's details, including whether it is an internal or external account.