Business Day Math — holiday-aware date calculations

Business Days Calculator API.

What it does

Business Day Math calculates business-day dates and counts using real public-holiday calendars for US, GB, CA, AU, DE, FR, and IN. Send a base date and a mode, and get a calendar-aware result back without having to hard-code weekend or holiday rules.

Use add mode to move forward or backward by a number of business days from a given date. Use count mode to measure the number of business days between a start and end date, with the end date treated as exclusive. Use is_business_day mode to check whether a date falls on a business day for the selected country. Use holidays mode to list the holidays for a given year and country.

The request body accepts date, start, end, days, mode, year, and country. The response returns mode, input, result, country, business_days, result_weekday, and holidays_skipped. That makes it straightforward to plug Business Day Math into scheduling flows, settlement logic, SLA calculations, or any workflow that needs to skip weekends and country-specific public holidays.

If you need date arithmetic that matches real business calendars instead of generic weekday math, Business Day Math gives you the result in a simple JSON response.

Quickstart

Add a small number of business days to a date.

curl -X POST "http://localhost:8080/creightonnick0/business-day-math" \
  -H "apy-token: $APY_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"mode":"add","date":"2026-12-23","days":3,"country":"US"}'

Note: Supported countries: US, GB, CA, AU, DE, FR, and IN. Holiday calendars: Public holidays are calculated for these countries using country-specific holiday rules. Countries outside this list are not currently supported.

What you'll get back

Returns a JSON object with these top-level fields: mode and input as strings, result and country as strings, business_days as an integer, result_weekday as a string, and holidays_skipped as an array of objects with date and name string fields.

{
  "mode": "add",
  "input": "2026-12-23",
  "result": "2026-12-28",
  "country": "US",
  "business_days": 3,
  "result_weekday": "Monday",
  "holidays_skipped": []
}

About this endpoint

What it does

Calculates business-day results using public-holiday calendars for the supported countries. Depending on mode, it can add business days to a date, count business days in a range, check whether a date is a business day, or return holidays for a year.

Request Body

Parameter	Type	Mandatory	Description
end	String	No	Range end in `YYYY-MM-DD`, exclusive. Used in `count` mode.
date	String	No	Base date in `YYYY-MM-DD`. Used in `add` and `is_business_day` modes.
days	Integer	No	Business days to add. Use a negative value to subtract. Used in `add` mode.
mode	String	No	Operation mode. Allowed values: `add`, `count`, `is_business_day`, `holidays`.
year	Integer	No	Year for `holidays` mode.
start	String	No	Range start in `YYYY-MM-DD`. Used in `count` mode.
country	String	No	ISO country code for the holiday calendar. Allowed values: `US`, `GB`, `CA`, `AU`, `DE`, `FR`, `IN`.

Response

Returns a JSON object with mode, input, result, and country string fields, plus business_days as an integer, result_weekday as a string, and holidays_skipped as an array of objects. Each object in holidays_skipped contains date and name string fields.

Parameter	Type	Mandatory	Description
mode	String	No	Operation mode used for the response.
input	String	No	Input value associated with the request.
result	String	No	Computed result value.
country	String	No	ISO country code associated with the holiday calendar.
business_days	Integer	No	Number of business days calculated.
result_weekday	String	No	Weekday for the computed result.
holidays_skipped	Object Array	No	Holidays skipped during the calculation. Each item contains `date` and `name` string fields.

Body

Name

Type

Description

bodyOPTIONAL

object

—

Quickstart

What you'll get back

About this endpoint

What it does

Request Body

Response

Body

Errors any endpoint can return