🇯🇵 Japan Toolkit API

Free Japan data for developers, everywhere. No API keyCORS enabledFree forever tier

Japanese national holidays, business-day checks, era (wareki) conversion, kana → romaji, JST now, and fictional Japanese test users — the fiddly Japan-specific logic you do not want to re-implement, as one simple JSON API.

Try it live

Click the button — the response appears here.

Endpoints

GET /v1/holidays?year=2026
All Japanese national holidays for a year, with English and Japanese names. Includes substitute and citizen's holidays.

GET /v1/holidays/next
The next national holiday from today (JST), or from ?from=YYYY-MM-DD.

GET /v1/is-business-day?date=2026-01-12
Is it a business day in Japan? Returns weekend, holiday and era info too.

GET /v1/business-days?from=2026-01-01&to=2026-01-31
Count business days between two dates (inclusive).

GET /v1/era?date=2026-11-10
Gregorian → Japanese era (wareki). Reverse: ?era=Reiwa&year=8.

GET /v1/convert?text=トウキョウ&to=romaji
Convert kana text. to = romaji | hiragana | katakana.

GET /v1/fake/users?count=5&seed=42
Fictional Japanese users for testing and i18n demos. Same seed = same users. Emails always use example.com.

GET /v1/now
Current time in Japan (JST), with era, holiday and business-day status.

Example

curl "https://m-japan-api.sannon2026.workers.dev/v1/holidays/next"

{
  "date": "2026-11-23",
  "name": "Labor Thanksgiving Day",
  "name_ja": "勤労感謝の日",
  "days_until": 13
}

Rules

No sign-up, no key. Please keep usage reasonable (cache holiday responses — they never change for a given year). Holiday calculation covers 2020–2030 rules including substitute / citizen's holidays; always verify against official sources for legal use. Fake users are fictional.