Non-Working Days vs The Calendar

icsdb is an open-data repository of pre-built .ics calendar files enumerating official non-working days for France (and its overseas territories), Belgium, Germany, Ireland, Switzerland, the UK's home nations, and the US, maintained on GitHub rather than served through a query API. Consumers fetch the raw .ics files directly off raw.githubusercontent.com (which serves them with open CORS) and import them into any calendar tool or icalendar-parsing library; there's no key, rate limit, or cost, but the project itself has had no commits since 2020.

The Calendar publishes pre-generated, static JSON (and downloadable .ics) files for US federal and all-50-state holidays (2025–2028), 30 countries' public holidays, plus FOMC meeting dates, US tax deadlines, market holidays, and key-date calendars for a dozen sports leagues. Every one of its 99 documented endpoints is a flat file behind Cloudflare, so there's no authentication, no rate limit, and CORS is wide open — licensed CC BY 4.0 as long as you link back.