Festivo Holiday API
Public holiday API service for several supported countries.
Calendarific is a simple way to get all holidays for any country in the world via a JSON API
Public holidays for more than 90 countries
Check if a date is a Russian holiday or not
Convert between Gregarian and Hebrew, fetch Shabbat and Holiday times, etc.
Display, create and modify Google calendar events
API for obtaining information about holidays.
Protestant liturgical calendar