Hebrew Calendar vs Nager.Date

Hebcal converts between Gregorian and Hebrew dates and computes Shabbat start/end times, holiday dates, Torah readings, and the Daf Yomi study cycle for any location, driven by the same open-source engine (@hebcal/core) that runs the hebcal.com website. Every endpoint is keyless JSON (or RSS/iCal on other routes) under a Creative Commons Attribution 4.0 license, so results can be reused commercially as long as Hebcal is credited. It's rate-limited to keep the free service polite — no more than 90 requests per 10-second window — and the once-http-only backend now serves over HTTPS as well.

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.