REST and JSON over 241 jurisdictions. Every field carries the authority behind it and how well it is evidenced.
For the systems that cannot ask a person: payroll runs, settlement engines, ERP calendars, routing and scheduling.
Not a list of dates. A row that says what it is, what it closes, who declared it, and how sure we are.
GET /v1/jurisdictions/DE/observances?from=2026-12-01 { "id": "christmas_day", "date": "2026-12-25", "scope": "national", "impact": "closed_general", "assurance": "verified", // verified · corroborated · compiled "source": "de-bmi-feiertage", "edition": "2026.08" }
Dates computed from rules should be cached. Charging per request would punish the behaviour we recommend.
A company operating in thirty countries knows it needs thirty. Nobody knows their annual call count.
The edition you cited stays retrievable. A later one never silently replaces it.
Every field says whether it was verified against an authority, corroborated, or computed from a rule.