Check a business day / 営業日かどうかの判定

Check whether a date is a business day in Japan, and if not, why (weekend, holiday name, bank closure, or a custom closed day). reason is Japanese text; reason_code is one of weekend, holiday, bank_closure, extra_holiday (null on business days). flags: estimated/unverified when the year's holidays are an estimate. / その日が営業日かどうかと、休みの理由（土日・祝日の名前・銀行の休業日・指定された休日）。reason_code は weekend・holiday・bank_closure・extra_holiday。

get/v1/business-days/check

Request

  • Base URL: https://biz.ossalt.jp
  • URL: https://biz.ossalt.jp/v1/business-days/check
  • Auth: none declared

Query parameters

datestring required

Date (YYYY-MM-DD) / 日付

calendar'standard' | 'bank'

"standard": weekends and national holidays are closed. "bank": also closed Dec 31 - Jan 3 (Japanese bank holidays). / standard：土日・祝日が休み。bank：加えて12月31日〜1月3日が休み（銀行の休業日）

extra_holidaysstring
Example:2026-08-13,2026-08-14

Additional company-specific closed days (e.g. summer break). / 会社独自の休み (comma-separated / カンマ区切り)

extra_business_daysstring
Example:2026-08-13,2026-08-14

Days treated as business days even if they are weekends or holidays. / 休日でも営業日とする日 (comma-separated / カンマ区切り)

Response

OK

resultobject required

The answer / 結果

sourceobject required

Source and verification / 出典と照合の状況

as_ofstring required

Reference date in Japan time (YYYY-MM-DD) / 基準日（日本時間）

notesstring[] required

Assumptions such as estimated values / 前提（見込みの値など）

flagsstring[] required

flags holds machine-readable codes: estimated (a value is an estimate, e.g. a future equinox day — tell the user), unverified (year not yet checked against Cabinet Office data — tell the user), assumes_current_era (a future date written in the current era — tell the user), outside_era (the era date given is outside that era), weekday_mismatch, closed (the company's registry record is closed — tell the user), excluded_from_search, truncated, not_found, exact_match_only, partial, ambiguous, city_not_found, ambiguous_city.

Changes

No recorded changes to this operation across all 1 revision of this API.