Public APIs about Calendar

Worldwide Holidays and Working Days

Catholic liturgical calendar

Lookup for a name and returns nameday date

Display, create and modify Google calendar events

Convert between Gregorian and Hebrew, fetch Shabbat and Holiday times, etc

Historical data regarding holidays

Protestant liturgical calendar

Public holidays for more than 90 countries

Provides namedays for multiple countries

Database of ICS files for non working days

Check if a date is a Russian holiday or not

Data on national, regional, and religious holidays via API

A REST API to convert UnixTime to DateTime and DateTime to UnixTime

Bank holidays in England and Wales, Scotland and Northern Ireland

A (satirical) Evangelical liturgical calendar

Fastest and most advanced public holiday and observance service on the market