| Abstract Public Holidays | Access national, regional, and religious holidays worldwide via API | apiKey | ✓ | ✓ | |
| Calendarific | Global holiday and observance API for countries, regions, and religions | apiKey | ✓ | ? | |
| Church Calendar | Catholic liturgical calendar with daily readings and feast days | No | ✗ | ? | |
| Czech Namedays Calendar | Lookup Czech name days and retrieve corresponding celebration dates | No | ✗ | ? | |
| Festivo Public Holidays | Advanced and fast public holiday and observance service | apiKey | ✓ | ✓ | |
| Google Calendar | Create, read, and modify Google Calendar events programmatically | OAuth | ✓ | ? | |
| Hebrew Calendar | Convert between Gregorian and Hebrew calendars, fetch Shabbat and holiday times | No | ✗ | ? | |
| Holidays | Provides historical and upcoming public holiday data | apiKey | ✓ | ? | |
| LectServe | Protestant liturgical calendar API | No | ✗ | ? | |
| Nager.Date | Provides public holidays for more than 90 countries in JSON format | No | ✓ | ✗ | |
| Namedays Calendar | Fetch name days for multiple countries and regions | No | ✓ | ✓ | |
| Non-Working Days (ICS) | Database of ICS files listing non-working days for various regions | No | ✓ | ? | |
| Non-Working Days API | Check working, non-working, or short days for Russia, CIS, USA and others | No | ✓ | ✓ | |
| Russian Calendar | Check if a date is a Russian holiday or not via API | No | ✓ | ✗ | |
| UK Bank Holidays | Official UK government API for bank holidays across England, Scotland, Wales, and Northern Ireland | No | ✓ | ? | |