Generic worldwide holiday APIs return a flat list of Korean holidays and stop there — and many miss substitute holidays (대체공휴일), which is exactly what breaks business-day math. This endpoint returns the full statutory set, including substitutes, with bilingual names.
Whether you're computing shipping ETAs, booking slots or business days, you need the real Korean public-holiday calendar — substitute holidays included. This API gives you the year's holidays, plus a one-call check for whether any specific date is a holiday.
| GET | /v1/holidays?year=2026 |
All Korean public holidays for a year, including substitute holidays (대체공휴일). |
| GET | /v1/holidays/is?date=2026-09-25 |
Is this date a Korean public holiday? Returns the holiday and weekday. |
| GET | /v1/today |
Today's Korean date (KST) and whether it is a public holiday. |
curl "https://korea-calendar-api.kunstudio.workers.dev/v1/holidays/is?date=2026-09-25"{
"date": "2026-09-25",
"is_holiday": true,
"holiday": {
"date": "2026-09-25",
"name": "추석",
"name_en": "Chuseok (Korean Thanksgiving)",
"substitute": false
},
"weekday": "Fri"
}No API key is needed on the origin to try this — it is rate-limited for fair evaluation. See the OpenAPI spec for the full schema.
substitute: true so you can treat them distinctly if needed.Building a Korean fortune (사주/saju) app? Pair this with the KunStudio Saju API for a full four-pillars reading over REST.