GET /v1/add-business-days

Parameters

Name	Type	Required	Description
`date`	string	Yes	Starting date in `YYYY-MM-DD` format. Must be within supported range.
`country`	string	Yes	ISO 3166-1 alpha-2 country code. Case-insensitive.
`days`	integer	Yes	Business days to add. Positive = forward, negative = backward, zero = no-op. Must be a base-10 integer within signed 32-bit range.
`region`	string	No	ISO 3166-2 subdivision suffix. Requires paid plan.

Request

curl -X GET "https://jday-api.jday.workers.dev/v1/add-business-days?date=2026-04-01&country=DE&days=10" \
  -H "Authorization: Bearer jday_live_xxx" \
  -H "Accept: application/json"

Response

{
  "start_date": "2026-04-01",
  "business_days_added": 10,
  "end_date": "2026-04-16",
  "country": "DE",
  "region": null,
  "holidays_skipped": [
    {
      "date": "2026-04-03",
      "official_date": null,
      "name": "Good Friday",
      "local_name": null,
      "type": "public",
      "date_accuracy": "exact"
    },
    {
      "date": "2026-04-06",
      "official_date": null,
      "name": "Easter Monday",
      "local_name": null,
      "type": "public",
      "date_accuracy": "exact"
    }
  ],
  "weekends_skipped": 4,
  "calendar_days_elapsed": 15
}

Response Fields

Field	Type	Description
`start_date`	string	The input date.
`business_days_added`	integer	Echoes the signed input value.
`end_date`	string	The computed result date.
`country`	string	Normalized country code.
`region`	string \| null	Region code if provided, otherwise `null`.
`holidays_skipped`	array	Holiday records on traversed non-weekend dates. Sorted chronologically.
`weekends_skipped`	integer	Absolute count of traversed weekend dates. Always non-negative.
`calendar_days_elapsed`	integer	Signed. Positive forward, negative backward, zero for `days=0`.

Counting Rule

The start date is never counted.
Computation moves one calendar day at a time in the sign direction of days.
Only business days count toward the target.

days = 0

Returns the input date unchanged:

holidays_skipped: []
weekends_skipped: 0
calendar_days_elapsed: 0

Overlap Rule

When a holiday falls on a weekend:

The weekend date counts toward weekends_skipped
holidays_skipped includes only holidays on traversed non-weekend dates
Multiple holidays on the same non-weekend date all appear in holidays_skipped

days Validation

Missing → 400 missing_parameter
Must be a base-10 integer string
No decimals, no scientific notation
Must fit signed 32-bit integer range
Invalid → 400 invalid_days

Boundary Behavior

If the computed end_date would fall outside the supported range (2025-01-01 to 2027-12-31), the API returns 400 date_out_of_range before performing expensive traversal.

Error Cases

Condition	Error
Missing `date`, `country`, or `days`	`400 missing_parameter`
Malformed date	`400 invalid_date`
Invalid days value	`400 invalid_days`
Date outside range	`400 date_out_of_range`
Computed result outside range	`400 date_out_of_range`
Unknown country	`400 invalid_country`
Invalid region	`400 invalid_region`
Region on Free plan	`403 plan_upgrade_required`

GET /v1/add-business-days

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