Google Calendar vs Namedays Calendar

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.

This API looks up which name(s) are celebrated on a given calendar date — or which date a given name falls on — across roughly 40 countries' nameday traditions, via a documented OpenAPI v2 surface (/today, /tomorrow, /yesterday, /getdate) served as JSON. It's a personal open project by its maintainer (Michal Abaline) with no signup, no API key, and no rate limiting, positioned as a lighter keyless alternative to older nameday lookup services.