Returns the complete list of all countries in the world with full country data. This is the main bulk endpoint - you get everything from country codes and capitals to currencies, languages, population, borders, timezones, and flag URLs. The response is a JSON array with ~250 country objects. Use this when you need the entire dataset, or combine with the fields parameter to limit which data fields come back.
Original spec description
Returns data for all countries. The 'fields' parameter is required to limit the response size (max 10 fields).