Business days calculator: add or count working days with your weekend mask and holiday list

Business days calculator with a caller-supplied calendar: add or subtract N working days from a date, or count the working days between two dates. The weekend is a weekday mask (Friday-Saturday and Sunday-only weeks work) and holidays are an explicit date list, so nothing depends on a stale holiday table. Returns the result date, the day count and the skipped dates with reasons. The skipped list is capped at 1,000 entries (skipped_truncated flags it); skipped_total is always exact.

Output (data): add: result (YYYY-MM-DD), from, days, calendar_days_spanned, skipped [{date, reason weekend|holiday, weekday}] (first 1,000), skipped_total, skipped_truncated. count: business_days, calendar_days, weekend_days, holiday_days, holidays_matched, direction (forward|backward) (holidays on a weekend are reported as weekend, never as holiday). count is half-open [from, to) unless inclusive says otherwise; when to precedes from the same interval is counted backwards and business_days is still a non-negative count. skipped is in the order the dates were traversed and lists at most 1,000 entries; skipped_total is the full count and skipped_truncated is true when the list was cut (the cap only binds for days beyond roughly 1,400 working-day skips, e.g. days near 3,650 with a two-day weekend); result, calendar_days_spanned and skipped_total are always exact.

Deterministic: identical input returns identical output, so the response is served with Cache-Control: private, max-age=31536000, immutable (the paying client may cache it indefinitely; shared caches must not, because the response is paid).

Price: $0.05 USDC per call (x402, Base). Route contract version 1.0.0. Docs: https://api.duoleads.com/docs#time-business-days