Google Calendar vs Non-Working Days

The Google Calendar API reads and writes events, calendars, free/busy data, and reminders for any Google account that's granted OAuth consent, with push-notification channels available so an app can watch a calendar for changes instead of polling it. It's the same REST API that powers Calendar add-ons and third-party scheduling tools like Calendly. Usage is free under Google's shared per-minute and per-project quotas (10,000 requests/minute/project as of the May 2026 quota update); there's no separate paid tier for the API itself, only future overage billing above a 1,000,000-requests-a-day threshold.

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.