Seller CredentialsThe merchant-integration merchant credentials for a downloadable cart seller.client_idstringOptionalThe client ID of the seller.Length1 <= length <= 255client_secretstringOptionalThe client secret of the seller.Length1 <= length <= 255payer_idstringOptionalThe payer ID of the seller and the pattern is not provided because the value is defined by an external party.Length1 <= length <= 255