Nager.Date vs Namedays Calendar

Nager.Date is a free, open-source public holiday API covering more than 100 countries, with endpoints for a year's full holiday list, the next public holiday, whether today is a holiday, and country/county metadata — all keyless JSON with no rate limiting. It's maintained on GitHub by a single developer and is popular as the default holiday backend baked into several scheduling and HR libraries specifically because it needs no signup.

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.