caldays vs Namedays Calendar

Caldays provides free public holiday data for 206 countries in JSON format, plus long-weekend calculations and a world clock endpoint. Anonymous use is capped at 10,000 requests per day; a metered API key raises the limit for higher-volume needs. The holiday data carries a CC BY 4.0 licence, so users must credit Caldays in their app.

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.