get https://api-demo.single-invoice.co/v2/lookups/countries
Provides a list of all the support countries along with their ISO ISO 3166-1 alpha-2 country code.
This will return a JSON-formatted list of all the countries along with their two letter county code as defined by ISO 3166-1 alpha-2 - for example, France is "FR" and the United Kingdom is "GB".
These codes are typically used when searching for transactors. This method can (for example) be used to populate a dropdown of countries in a search form. (The contents are not expected to change so it should be safe to locally cache these values for long periods of time.)