# KoreaKit

> Korean public holidays (incl. 2026 노동절/제헌절 and 대체공휴일 substitute rules), business days, Korean lunar calendar, and Hangul text utilities. Paid per call with x402 v2 (USDC, eip155:8453). No API key.

Every endpoint is GET with query parameters and returns JSON. Without a PAYMENT-SIGNATURE header you get HTTP 402 with a PAYMENT-REQUIRED header (base64 JSON). Invalid parameters return a free 400 with a JSON "error" message, and parameters are checked before any payment is verified or settled, so a bad request is never charged. The bare URL with no parameters returns 402 (for discovery).

## Endpoints

- [/v1/holidays](https://koreakit.celee.workers.dev/v1/holidays?year=2026): South Korea public holidays for a year (2015-2050): 설날·추석 (lunar), 대체공휴일 substitute holidays, election days, temporary holidays, and the 2026 additions 노동절 (May 1) and 제헌절 (Jul 17). Korean and English names. KASI lunar data. Params: year: Gregorian year, 2015-2050. Price $0.003.
- [/v1/holidays/check](https://koreakit.celee.workers.dev/v1/holidays/check?date=2026-05-01): Check whether a date is a South Korea public holiday, weekend, or business day (영업일), with holiday names. Includes 대체공휴일 and 2026 노동절·제헌절. Params: date: YYYY-MM-DD. Price $0.003.
- [/v1/business-days/add](https://koreakit.celee.workers.dev/v1/business-days/add?date=2026-09-23&days=3): Add or subtract N South Korea business days (영업일) to a date, skipping weekends and all Korean public holidays incl. substitute holidays. Use for payment due dates, delivery and contract deadlines. Params: date: Start date YYYY-MM-DD (not counted); days: Business days to add; negative to subtract (|days| <= 3650). Price $0.003.
- [/v1/business-days/count](https://koreakit.celee.workers.dev/v1/business-days/count?from=2026-09-21&to=2026-09-30): Count South Korea business days (영업일) between two dates, inclusive of both ends, excluding weekends and Korean public holidays. Params: from: YYYY-MM-DD (inclusive); to: YYYY-MM-DD (inclusive). Price $0.003.
- [/v1/lunar/to-solar](https://koreakit.celee.workers.dev/v1/lunar/to-solar?date=2026-08-15&leap=false): Convert a Korean lunar calendar date (음력) to the Gregorian date (양력) with 간지 (sexagenary) names, KASI standard. For birthdays, 제사, traditional events. Params: date: Lunar date YYYY-MM-DD; leap (optional): true if the lunar month is a leap month (윤달). Price $0.003.
- [/v1/lunar/from-solar](https://koreakit.celee.workers.dev/v1/lunar/from-solar?date=2026-09-25): Convert a Gregorian date (양력) to the Korean lunar calendar date (음력), leap-month flag and 간지 names, KASI standard. Params: date: Gregorian date YYYY-MM-DD. Price $0.003.
- [/v1/text/amount](https://koreakit.celee.workers.dev/v1/text/amount?n=1234500): Write a number as a Korean amount in words: spoken form, formal 일금…원정 contract form for invoices and contracts, and 갖은자 hanja (壹貳參). Up to 20 digits. Params: n: Non-negative integer, commas allowed. Price $0.003.
- [/v1/text/josa](https://koreakit.celee.workers.dev/v1/text/josa?word=%EC%84%9C%EC%9A%B8&josa=%EC%9C%BC%EB%A1%9C): Choose the grammatically correct Korean particle (은/는, 이/가, 을/를, 과/와, 으로/로 …) for a word, number or acronym, based on its final consonant (받침). For templated Korean text generation. Params: word: Word, number or acronym; josa: Either form of the particle, e.g. 을 or 을/를. Price $0.003.
- [/v1/text/romanize](https://koreakit.celee.workers.dev/v1/text/romanize?text=%EA%B2%BD%EB%B3%B5%EA%B6%81&mode=general): Romanize Korean (Hangul) text with the official Revised Romanization rules incl. sound changes (종로 jongno, 신라 silla). mode=name for personal names with common surname spellings (Kim, Lee, Park). Params: text: Korean text, up to 2000 chars; mode (optional): general (default) or name. Price $0.003.
- [/v1/validate/brn](https://koreakit.celee.workers.dev/v1/validate/brn?number=220-81-62517): Validate the checksum of a South Korea business registration number (사업자등록번호, 10 digits) and classify the entity type (individual, corporation HQ/branch, non-profit). Offline checksum only. Params: number: 10 digits, hyphens allowed. Price $0.003.

## Discovery

- [x402 resources](https://koreakit.celee.workers.dev/.well-known/x402)
- [OpenAPI](https://koreakit.celee.workers.dev/openapi.json)
- [Free holiday tables](https://koreakit.celee.workers.dev/holidays/2026)

## Contact

Operated by WiseLake Inc. Contact: wiselake@wiselake.ai