Developer layer

Holiday API for dates, holidays, and countdowns

Use WhenIsDate as a structured holiday and event date data source. The first public version exposes static JSON and calendar files while the Cloudflare Workers API is prepared.

Current public data endpoints

/data/events.json lists event slugs, titles, and categories.

/ics/thanksgiving-2026.ics is an example calendar event file.

Example response

{
  "event": "thanksgiving",
  "year": 2026,
  "date": "2026-11-26",
  "weekday": "Thursday",
  "country": "US",
  "calendar_file": "https://whenisdate.com/ics/thanksgiving-2026.ics"
}

Planned API routes

/api/v1/holidays?country=us&year=2026
/api/v1/events/thanksgiving?year=2026
/api/v1/countdown?event=black-friday