Business-Day Oracle — working days, deadlines and business-day conventions for 250 countries

MCP server + REST API. The date arithmetic every agent gets wrong once it leaves its home country: which days are the weekend (Fri–Sat in Saudi Arabia and Kuwait, Sun-only in parts of Asia, Sat–Sun in the UAE since 2022), which holidays apply in this state or province, what "within 10 business days" lands on, and how a payment date rolls under ISDA modified following. 250 countries, 35 with sub-national calendars (US states, German Länder, Canadian provinces, Indian states, Australian states, UAE emirates…), 30 financial-market calendars (NYSE, LSE, Xetra, HKEX, JPX, Tadawul…).

Every answer states data_confidence, lists estimated_items (lunar / moon-sighted holidays are projections until officially announced — the response says so per date), cites sources for the calendar used, and compute_deadline returns a step-by-step explanation plus a disclaimer. Deterministic code; no AI inside; no query logging.

Tools (8)

tool	use when	price
is_working_day	one date → working day? why not (weekend / holiday name / observed / projected)	$0.002
add_working_days	"N business days from…" — delivery promises, SLA clocks, payment terms; lists every skipped day	$0.008
working_days_between	count working days with endpoint control; leave cost, lateness	$0.008
roll_date	following / modified following / preceding / modified preceding on a country or market calendar	$0.008
compute_deadline	"within 30 days / 10 working days / 3 months" with explicit counting rules and an explanation trail	$0.008
list_holidays	a year's holidays, local + English names, observed/projected flags	$0.002
next_holiday	next N holidays with days_until	$0.002
list_calendars	country/market codes, legal weekend, subdivision codes, categories, languages, sources	free

Each calendar can be refined with subdivision, categories (public, bank, government, school…), a weekend override and extra_holidays (company closures), and include_estimated_holidays=false ignores projected dates until announced.

Example

// compute_deadline {"start_date": "2026-01-31", "period": 1, "unit": "months", "country": "KW"}
{
  "result": {
    "raw_deadline": "2026-02-28", "deadline": "2026-03-01", "deadline_weekday": "Sun",
    "rules": {"exclude_start_day": true, "convention": "following", "month_end_clamp": true, "include_estimated_holidays": true},
    "explanation": [
      "Start date 2026-01-31 (Sat), calendar KW.",
      "Added 1 month(s) → 2026-02-28 (Sat) (clamped to month end).",
      "2026-02-28 is weekend; rolled forward to 2026-03-01 (Sun)."
    ],
    "calendar": "KW", "weekend": ["FRI", "SAT"]
  },
  "data_confidence": "high",
  "sources": ["https://github.com/vacanza/holidays", "..."],
  "disclaimer": "Date arithmetic over public holiday calendars; not legal, tax or financial advice. ..."
}

Confidence, honestly

• high — fixed-date and rule-based holidays, weekends from the country's law.
• medium — the answer touched a lunar/moon-sighted holiday that is still a projection (named in estimated_items), or the caller overrode the weekend.
• Holiday data is compiled from public sources by python-holidays (version pinned and reported in data_version); it can lag official announcements. For UAE sector/emirate rules with official confirmation status, use the companion UAE Calendar Oracle.

Connect

• Apify (metered): Standby URL + /mcp, header Authorization: Bearer <your Apify token>.
• Self-hosted: claude mcp add bizday --transport http https://bizday.noahsarch.tech/mcp --header "X-API-Key: <key>" — one Noah's Arch key works across all our agents.
• REST: POST https://bizday.noahsarch.tech/v1/tools/<tool>; OpenAPI at /openapi.json, docs at /docs.

Not legal, tax or financial advice

Counting conventions differ by jurisdiction and contract; pass the rules that apply and verify deadlines that carry legal weight.

---

بالعربية

عرّاف أيام العمل — خادم MCP وواجهة REST لحساب أيام العمل والمواعيد النهائية وأعراف أيام العمل المصرفية في 250 دولة (35 منها بتقاويم على مستوى الولايات/الإمارات) و30 سوقاً مالياً. يعرف عطلة نهاية الأسبوع القانونية لكل دولة (الجمعة–السبت في السعودية والكويت، السبت–الأحد في الإمارات)، ويميّز العطلات القمرية التقديرية عن المؤكدة، ويعيد في كل إجابة مستوى الثقة والمصادر ومسار تفسير خطوة بخطوة. لا ذكاء اصطناعي داخلها ولا تسجيل للاستعلامات. حساب تواريخ وليس استشارة قانونية أو ضريبية أو مالية.