OpenDay API by JB Studio: US & Puerto Rico Holidays + Business Days

Every holiday and business day for the US and Puerto Rico, from the official sources.

OpenDay API answers "is it a business day?" and "what date is N business days from now?" for US federal, all 50 states + DC, Federal Reserve bank days and Puerto Rico, with every date tied to the law or official calendar it comes from.

What you can build

• Payroll dates. Move a payday that falls on a holiday to the right business day, using the state-employee calendar for each state, or Puerto Rico's government calendar (with its Sunday-to-Monday rule). Example: July 4, 2027 is a Sunday. In Puerto Rico it is observed on Monday, July 5, so is-business-day for 2027-07-05 and region PR returns false.
• ACH and bank settlement. Bank transfers follow the Federal Reserve calendar, where a Saturday holiday is not moved to Friday. Use calendar=banking. Example: Friday, July 3, 2026 is a federal day off, but a banking business day.
• Delivery estimates. "Arrives in 10 business days" from any start date, skipping weekends and holidays. Example: 10 business days after December 20, 2027 is January 5, 2028 on the federal calendar, and January 3, 2028 on the banking calendar.
• Legal and contract deadlines. "Within 10 business days" for a specific state or for Puerto Rico, counting only the days that state's offices are open. Example: count business days between two dates in US-TX, where weekend holidays are never moved to a weekday.
• Puerto Rico addresses and sales tax. Find the municipio of a ZIP code, list all 78 municipios, and get IVU rates with their legal citations. Example: ZIP 00680 is 94% in Mayagüez (primary), with small parts in San Germán and Añasco.

Why OpenDay

• Every date cites its official law or calendar, with a link and a source type (official or secondary-copy).
• Puerto Rico done right: three calendars (legal, government, banking), the Sunday-to-Monday rule, and the yearly government memo.
• All 50 states + DC, using each state's own state-employee calendar and weekend rule.
• Bank days, not just holidays: Federal Reserve rules.
• Bilingual: every holiday has English and Spanish names.
• Puerto Rico toolkit: municipios, ZIP code lookup and IVU rates from the Census Bureau and the Puerto Rico tax code.
• Honest data: every year is labeled official, computed or projected.

Coverage

Region	Calendars	Years	Verification
US federal (US)	federal (default): 11 federal holidays; optional Inauguration Day	2000-2100	2026 and 2027 official (checked against the federal holiday calendar); other years computed from 5 U.S.C. 6103
US banking (US, calendar=banking)	Federal Reserve holiday schedule	2000-2100	computed from the Federal Reserve rules
50 states + DC (US-CA, US-TX, ..., US-DC)	state (default): state-employee holidays; banking	2026-2100	2026: 35 official, 16 computed. 2027: 16 official, 26 computed, 9 projected. Later years computed or projected
Puerto Rico (PR)	government (default), legal, banking	2000-2100	government 2027 official (OATRH memo); other years and calendars computed
Puerto Rico toolkit (/v1/pr/...)	78 municipios, 132 ZIP codes, IVU rates	Current	official (Census 2020; Código de Rentas Internas de 2011)

The regions endpoint lists every region, its calendars, supported years and the verification status for each year.

How to use it

Standby (HTTP API)

Call the Actor's Standby URL with your API token. The endpoints are the same as the REST API:

Endpoint	Purpose
GET /v1/holidays?country=PR&year=2027	Holidays for a year (calendar, dateBasis, include optional)
GET /v1/is-business-day?date=2027-07-05&region=PR	Is this date a business day?
GET /v1/business-days/add?start=2027-12-20&days=10&region=US	Add or subtract business days
GET /v1/business-days/between?start=2027-01-01&end=2027-01-31&region=US-TX	Count business days between two dates
GET /v1/regions	Supported regions, calendars, years and sources
GET /v1/pr/municipios, GET /v1/pr/municipios/{id}	Puerto Rico municipios
GET /v1/pr/zip/00680	Municipio(s) of a Puerto Rico ZIP code
GET /v1/pr/ivu	IVU sales and use tax rates with citations

GET https://<your-standby-url>/v1/is-business-day?date=2027-07-05&region=PR
Authorization: Bearer <YOUR_API_TOKEN>

{
  "data": {
    "date": "2027-07-05",
    "region": "PR",
    "calendar": "government",
    "isBusinessDay": false,
    "reason": "holiday",
    "dayOfWeek": 1,
    "holidays": [
      {
        "id": "independence-day",
        "date": "2027-07-04",
        "observedDate": "2027-07-05",
        "nameEn": "US Independence Day",
        "nameEs": "Día de la Independencia de los Estados Unidos",
        "type": "legal",
        "source": "Ley 26-2017, Art. 2.05, as amended by Ley 8-2021 and Ley 117-2022; OATRH Memorando Especial 12-2026 (July 17, 2026)",
        "sourceUrl": "https://docs.pr.gov/files/OATRH/Contenido%20Nuevo/Memos/ME%2012-2026..pdf",
        "sourceType": "official"
      }
    ]
  },
  "meta": {
    "calendar": "government",
    "verificationStatus": "official",
    "note": "Confirm official proclamations."
  }
}

(Shortened. Full responses include every field, such as scope, paidDayOff and meta.references.)

Errors use one shape: { "error": { "code", "message", "details" } }, for example VALIDATION_ERROR with a list of the parameters to fix.

Batch (run with input)

Send up to 1,000 requests in one run. Each request is an endpoint plus the same parameters as the HTTP API:

{
  "requests": [
    { "endpoint": "holidays", "params": { "country": "PR", "year": 2027 } },
    { "endpoint": "is-business-day", "params": { "date": "2027-07-05", "region": "US" } },
    {
      "endpoint": "business-days/add",
      "params": { "start": "2027-12-20", "days": 10, "region": "US", "calendar": "banking" }
    }
  ]
}

Each request becomes one dataset item:

{
  "endpoint": "business-days/add",
  "params": { "start": "2027-12-20", "days": 10, "region": "US", "calendar": "banking" },
  "ok": true,
  "summary": "2027-12-20 +10 business days = 2028-01-03",
  "data": {
    "start": "2027-12-20",
    "days": 10,
    "region": "US",
    "calendar": "banking",
    "result": "2028-01-03"
  },
  "meta": {
    "calendar": "banking",
    "verificationStatus": "computed",
    "note": "Confirm official proclamations."
  }
}

An invalid request returns "ok": false with the same error shape and does not stop the run.

Puerto Rico toolkit

Reference data for Puerto Rico addresses and sales tax, from official sources only:

Endpoint	Batch name	What it returns
GET /v1/pr/municipios	pr/municipios	All 78 municipios with code, official name (with accents), ASCII name and slug
GET /v1/pr/municipios/{id}	pr/municipio	One municipio by code (72097) or name (Mayagüez, mayaguez); accents and case do not matter
GET /v1/pr/zip/{zip}	pr/zip	Every municipio a ZIP code covers, with its land-area share and the primary one marked
GET /v1/pr/ivu	pr/ivu	IVU rates (state 10.5%, municipal 1%, total 11.5%, services 4%), each citing the Código de Rentas Internas section

• Address cleanup: turn a ZIP code into the right municipio, even when the ZIP crosses municipio lines.
• Forms and dropdowns: the official names with accents, plus ASCII names and slugs for URLs.
• Checkout and invoicing: show the IVU rate together with the section of law behind it.

GET https://<your-standby-url>/v1/pr/zip/00680
Authorization: Bearer <YOUR_API_TOKEN>

{
  "data": {
    "zip": "00680",
    "primary": {
      "code": "72097",
      "name": "Mayagüez",
      "nameAscii": "Mayaguez",
      "slug": "mayaguez",
      "share": 0.9415,
      "primary": true
    },
    "municipios": [
      {
        "code": "72097",
        "name": "Mayagüez",
        "nameAscii": "Mayaguez",
        "slug": "mayaguez",
        "share": 0.9415,
        "primary": true
      },
      {
        "code": "72125",
        "name": "San Germán",
        "nameAscii": "San German",
        "slug": "san-german",
        "share": 0.0343,
        "primary": false
      },
      {
        "code": "72011",
        "name": "Añasco",
        "nameAscii": "Anasco",
        "slug": "anasco",
        "share": 0.0241,
        "primary": false
      }
    ]
  },
  "meta": {
    "dataset": "pr-zip-municipios",
    "sourceUrl": "https://www2.census.gov/geo/docs/maps-data/data/rel2020/zcta520/tab20_zcta520_county20_natl.txt",
    "verificationStatus": "official",
    "verificationNote": "Based on 2020 Census ZIP Code Tabulation Areas (ZCTAs), which closely approximate USPS ZIP codes; ...",
    "note": "Confirm official proclamations."
  }
}

In a batch run: { "endpoint": "pr/zip", "params": { "zip": "00680" } } gives the summary ZIP 00680: Mayagüez 94%, San Germán 3%, Añasco 2%.

Sources: US Census Bureau 2020 county FIPS codes and 2020 ZCTA to County relationship file; Código de Rentas Internas de Puerto Rico de 2011 (consolidated text from the Departamento de Hacienda). ZIP codes are matched with Census ZIP Code Tabulation Areas, which closely approximate USPS ZIP codes. The IVU data is general information, not tax advice.

Sources and accuracy

• Every holiday includes source (the statute, regulation or official calendar), sourceUrl and sourceType. News sites are never used as a source.
• official: the dates were confirmed on the jurisdiction's own official calendar for that year.
• computed: calculated from statute or written policy.
• projected: the list is set each year (for example by a governor), or a practice shown on an official calendar is applied to later years. The note names the official year it is based on.
• Each response's meta.verificationStatus tells you which applies.
• Known gaps: county-level days (for example, Mardi Gras in some counties), bargaining-unit-only days, and days granted year by year without an official list are not included yet. In the Puerto Rico toolkit, PO box-only ZIP codes (no Census ZCTA) return 404, and IVU exemptions and special rates are not included.

Results come from law and published schedules and may differ from a specific year's proclamation or an employer's own schedule. Confirm official proclamations.

Pricing

Pay per successful request. See the Pricing tab.

Errors, health checks and documentation requests are never charged.

En español

¿Es día laborable? La respuesta oficial para Puerto Rico y los 50 estados.

• Feriados de Puerto Rico correctos, con la ley citada en cada fecha. Calendario legal, de gobierno y bancario, con la regla de domingo a lunes y el memorando anual de la OATRH.
• Calendario de gobierno, banca y feriados legales, en un solo API. También días bancarios de la Reserva Federal y los calendarios de empleados estatales de los 50 estados y DC.
• Nombres en español para cada feriado, y cálculo de días laborables: ¿qué fecha será dentro de 10 días laborables?
• Herramientas de Puerto Rico: los 78 municipios (con acentos), el municipio de cada código postal y las tasas del IVU con su cita legal. Fuentes: Censo 2020 y Departamento de Hacienda. Información general, no constituye asesoría contributiva.

Se paga por cada solicitud exitosa. Consulte la pestaña de precios (Pricing).