CredentialSeller credentials.signatureobject<signature>OptionalThe signature portion of the seller credentials.signature properties3 propertiesapi_user_namestringOptionalThe API user name of the seller.api_passwordstringOptionalThe API password of the seller.signaturestringOptionalThe signature credential of the seller.certificateobject<certificate>OptionalA certificate for seller credentials.certificate properties4 propertiesapi_user_namestringOptionalThe API user name for the seller.api_passwordstringOptionalThe API password for the seller.fingerprintstringOptionalThe fingerprint.download_linkstringOptionalThe URL to download the certificate.