The checkout_id (or token) generated from your client.

Param used to identify the country in which Affirm is used and uses an "alpha-3" three-letter country code. Supported countries are the United States (USA), Canada (CAN), and the United Kingdom (GBR). If no value is entered, country-code will default to USA.

Optional param used to identify the language used in the browser expressed as the following- en_US if the country-code is set to USA, en_CA if the country-code is set to CAN, fr_CA for French Canadian, and if the country-code is set to GBR the affirm-locale will be en_GB for British English. If an affirm-locale is not defined, it will automatically default to English.