About HolidaySync
HolidaySync is a free, personalized global holiday calendar that brings together public holidays from 90+ countries, the Catholic liturgical calendar, and European nameday traditions — all in one place, with no account required.
Our Mission
The world is more connected than ever, yet staying informed about how different cultures mark time remains surprisingly hard. A global team member misses wishing a Polish colleague a happy nameday. A Catholic family doesn't realize Pentecost falls on a long weekend. A traveler books a flight on a national holiday when everything is closed.
HolidaySync exists to solve this. Our mission is simple: help people stay connected to global celebrations, cultural traditions, and religious observances — wherever they are in the world and however they mark time.
We believe a calendar should reflect the full richness of human culture, not just the single country you happen to live in. That's why HolidaySync lets you overlay public holidays from multiple countries, Catholic feast days, and European nameday traditions into one seamless view — personalized to you, for free, forever.
Who HolidaySync Is For
HolidaySync is designed for anyone whose life crosses cultural or national borders:
International Families
Keep track of holidays in every country your family has roots in — birthdays, namedays, and national celebrations all in one calendar.
Global Teams
Schedule meetings, plan sprints, and avoid booking across public holidays for colleagues in London, Warsaw, São Paulo, and Tokyo simultaneously.
Travelers
Know which days museums are closed, when local festivals happen, and which dates to avoid for business travel before you book.
Catholics & Christians
Follow the full liturgical year with accurate moveable feast dates for Easter, Ash Wednesday, Pentecost, Corpus Christi, and 35+ fixed feasts — computed fresh every year.
Nameday Trackers
Never miss a nameday again. Track celebrations for friends and family across 20+ European regions including Poland, Greece, Hungary, and more.
HR & Planners
Manage leave calendars across international offices, ensure compliance with local public holiday entitlements, and plan team schedules with confidence.
How HolidaySync Works
HolidaySync combines three independent data sources into a single, real-time calendar view — all processed in your browser with no data sent to our servers.
Public Holidays — Nager.at
Official public holiday data for 90+ countries is fetched live from the Nager.at Public Holidays API, an open-source, community-maintained dataset with contributions from government sources worldwide. Data updates automatically each year — no manual maintenance needed.
Namedays — nameday.abalin.net
Nameday data for 20+ European regions (Austria, Bulgaria, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Croatia, Hungary, Italy, Lithuania, Latvia, Poland, Russia, Sweden, Slovakia, Spain, and more) is fetched in real time from nameday.abalin.net.
Catholic Calendar — Built-In Algorithm
All Catholic feast dates are computed directly in your browser using the standard Gregorian Easter algorithm (Butcher's algorithm). This means no external API is needed for Catholic feast days — they are always accurate for any year, past or future, without an internet connection.
Your calendar preferences (country, nameday region, Catholic calendar toggle) are saved to your browser's localStorage so they're ready the next time you visit. Nothing is stored on our servers.
Data Accuracy Policy
HolidaySync strives to provide accurate, up-to-date holiday information. Our public holiday data comes from Nager.at, which sources directly from government publications and is maintained by a community of contributors. Catholic feast dates are computed mathematically using the Gregorian Easter algorithm and are accurate for any year. Nameday data is sourced from nameday.abalin.net.
While we take data quality seriously, government holiday legislation can change with little notice. For critical business, legal, or travel decisions, we strongly recommend verifying dates with official government or embassy sources. HolidaySync is provided as an informational tool.
If you notice an error in our holiday data, please contact us and we will investigate and update as quickly as possible.
Our Story
HolidaySync was founded to address a simple frustration: there was no single, free tool that combined public holidays, Catholic feast days, and European namedays into one personalized calendar view. Most calendar apps either focused on a single country or required a paid subscription for global coverage.
We built HolidaySync as a completely free, browser-based tool. There's no account, no data collection beyond anonymous analytics, and no subscription fee — ever. We believe access to global cultural and religious calendar information should be free and open to everyone.
The tool is built and maintained by a small team passionate about making global information accessible. We're constantly improving coverage, adding new countries, and refining the user experience based on your feedback.
Contact Us
We welcome questions, bug reports, feature requests, and general feedback. The best way to reach us is by email:
Follow HolidaySync
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