2s

List the official holidays for a country and year, with exact observed dates including substitute days (e.g. a Saturday July 4th observed on Friday). Query: country (ISO 3166-1 alpha-2, 200+ supported), year, optional region (subdivision code like CA for US-California or BY for DE-Bavaria), optional types filter (public, bank, school, optional, observance — comma-separated), optional lang (ISO 639-1) for localized names. Returns one item per holiday: { date (YYYY-MM-DD), name, type, substitute, rule }. Dates are computed from maintained per-country rules — including movable feasts and lunar-calendar holidays — so they stay correct year over year. Use for scheduling, delivery estimates, payment terms, and SLA math.