US Federal Holidays and Business Days

Exact U.S. federal holidays for any year 1971-2100 under 5 U.S.C. 6103: legal date, OPM observed date (Saturday -> Friday, Sunday -> Monday, so New Year's Day 2022 is observed Friday 2021-12-31) and the Federal Reserve closure date (Fed Banks stay OPEN the Friday before a Saturday holiday). Applies the rule history a model tends to get wrong: Juneteenth from 2021, MLK Day from 1986, Veterans Day on the 4th Monday of October 1971-1977, and Inauguration Day (DC area only, flagged optional). No network calls.

{
  "type": "object",
  "properties": {
    "year": {
      "type": "integer",
      "minimum": 1971,
      "maximum": 2100,
      "description": "Calendar year, 1971-2100."
    }
  },
  "required": [
    "year"
  ],
  "additionalProperties": false,
  "$schema": "http://json-schema.org/draft-07/schema#"
}

Says whether a date (1971-2100) is a business day on the U.S. federal (OPM) calendar or the Federal Reserve banking calendar, names the holiday if any, and returns the previous and next business day. The two calendars differ when a holiday falls on Saturday: 2026-07-03 is a federal holiday but a Fed banking day.

{
  "type": "object",
  "properties": {
    "date": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
    },
    "calendar": {
      "type": "string",
      "enum": [
        "federal",
        "fed_banking"
      ],
      "default": "federal",
      "description": "federal = OPM observance for federal employees (Saturday holiday -> Friday off). fed_banking = Federal Reserve Banks (Saturday holiday -> open Friday; Sunday -> closed Monday). Use fed_banking for ACH, wire and bank settlement dates."
    },
    "include_inauguration_day": {
      "type": "boolean",
      "default": false,
      "description": "federal calendar only: also close Inauguration Day (DC-area federal employees only, every 4 years)."
    },
    "extra_closed_dates": {
      "type": "array",
      "items": {
        "$ref": "#/properties/date"
      },
      "maxItems": 100,
      "description": "Extra closed dates to treat as holidays, e.g. a one-off executive order closure such as 2025-01-09."
    }
  },
  "required": [
    "date"
  ],
  "additionalProperties": false,
  "$schema": "http://json-schema.org/draft-07/schema#"
}

Adds (or with a negative number subtracts) N business days to a date, skipping weekends and observed U.S. federal or Federal Reserve holidays exactly. The start date is not counted. With 0, returns the start date if it is a business day, otherwise the next one. Lists every holiday skipped.

{
  "type": "object",
  "properties": {
    "start_date": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
    },
    "business_days": {
      "type": "integer",
      "minimum": -20000,
      "maximum": 20000,
      "description": "Business days to add; negative to go back."
    },
    "calendar": {
      "type": "string",
      "enum": [
        "federal",
        "fed_banking"
      ],
      "default": "federal",
      "description": "federal = OPM observance for federal employees (Saturday holiday -> Friday off). fed_banking = Federal Reserve Banks (Saturday holiday -> open Friday; Sunday -> closed Monday). Use fed_banking for ACH, wire and bank settlement dates."
    },
    "include_inauguration_day": {
      "type": "boolean",
      "default": false,
      "description": "federal calendar only: also close Inauguration Day (DC-area federal employees only, every 4 years)."
    },
    "extra_closed_dates": {
      "type": "array",
      "items": {
        "$ref": "#/properties/start_date"
      },
      "maxItems": 100,
      "description": "Extra closed dates to treat as holidays, e.g. a one-off executive order closure such as 2025-01-09."
    }
  },
  "required": [
    "start_date",
    "business_days"
  ],
  "additionalProperties": false,
  "$schema": "http://json-schema.org/draft-07/schema#"
}

Counts business days between two dates (1971-2100) on the U.S. federal or Federal Reserve calendar, excluding weekends and observed holidays. include_start and include_end default to true, like Excel NETWORKDAYS. If end is before start the count is negative. Lists the weekday holidays that were excluded.

{
  "type": "object",
  "properties": {
    "start_date": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
    },
    "end_date": {
      "$ref": "#/properties/start_date"
    },
    "include_start": {
      "type": "boolean",
      "default": true
    },
    "include_end": {
      "type": "boolean",
      "default": true
    },
    "calendar": {
      "type": "string",
      "enum": [
        "federal",
        "fed_banking"
      ],
      "default": "federal",
      "description": "federal = OPM observance for federal employees (Saturday holiday -> Friday off). fed_banking = Federal Reserve Banks (Saturday holiday -> open Friday; Sunday -> closed Monday). Use fed_banking for ACH, wire and bank settlement dates."
    },
    "include_inauguration_day": {
      "type": "boolean",
      "default": false,
      "description": "federal calendar only: also close Inauguration Day (DC-area federal employees only, every 4 years)."
    },
    "extra_closed_dates": {
      "type": "array",
      "items": {
        "$ref": "#/properties/start_date"
      },
      "maxItems": 100,
      "description": "Extra closed dates to treat as holidays, e.g. a one-off executive order closure such as 2025-01-09."
    }
  },
  "required": [
    "start_date",
    "end_date"
  ],
  "additionalProperties": false,
  "$schema": "http://json-schema.org/draft-07/schema#"
}

Computes an invoice due date from an issue date and net terms in calendar days (Net 30 = 30), then optionally rolls a weekend or U.S. holiday due date: following (next business day), preceding, or modified_following (next business day unless it crosses into the next month). Uses exact observed federal or Federal Reserve holidays.

{
  "type": "object",
  "properties": {
    "issue_date": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
    },
    "net_days": {
      "type": "integer",
      "minimum": 0,
      "maximum": 3650,
      "description": "Net terms in calendar days, e.g. 30 for Net 30."
    },
    "roll": {
      "type": "string",
      "enum": [
        "none",
        "following",
        "preceding",
        "modified_following"
      ],
      "default": "following",
      "description": "How to move a due date that is not a business day."
    },
    "calendar": {
      "type": "string",
      "enum": [
        "federal",
        "fed_banking"
      ],
      "default": "fed_banking",
      "description": "fed_banking (default) matches when banks settle payments; federal uses OPM observance."
    },
    "extra_closed_dates": {
      "type": "array",
      "items": {
        "$ref": "#/properties/issue_date"
      },
      "maxItems": 100,
      "description": "Extra closed dates to treat as holidays, e.g. a one-off executive order closure such as 2025-01-09."
    }
  },
  "required": [
    "issue_date",
    "net_days"
  ],
  "additionalProperties": false,
  "$schema": "http://json-schema.org/draft-07/schema#"
}