Church Calendar vs Hebrew Calendar

Church Calendar (calapi) serves the daily Roman Catholic liturgical calendar — season, week, feast rank, and liturgical color — for a given date and country-specific calendar variant, in English, Czech, Latin, or Spanish. It's a small keyless JSON API maintained by a Czech developer alongside the printed liturgical calendars he publishes. There's no pricing or account system of any kind; the only quirk is that its real backend still only serves plain HTTP, timing out on HTTPS.

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.