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Holiday D-day icon

Holiday D-day

Shows a D-day countdown to the next Korean public holiday

Works on
Edge
Version
3.0.2
Add to Edge

You know a holiday is coming up. You just don't know if it's in four days or in fourteen, so you open a calendar, count the rows, and forget again by tomorrow. This puts the number on your toolbar instead.

Holiday D-day shows a live D-day countdown to the next Korean public holiday, right on your browser toolbar. Always know how many days are left until the next day off — at a glance.

Screenshots

What it does

  • Next Holiday Countdown

    See exactly how many days remain until the next Korean public holiday.

  • Toolbar Badge

    A badge on the extension icon shows the D-day number without even opening the popup.

  • Holiday Details

    Open the popup to see the upcoming holiday's name and date.

  • Automatic Daily Update

    The countdown recalculates each day so it's always accurate.

  • Light / Dark Theme

    A clean popup that matches your preference.

When you'd reach for it

  • Deciding when to take leave

    The popup lists every public holiday left in the year with its weekday, so a holiday that lands on a Tuesday or a Thursday is easy to spot. Those are the ones worth burning a vacation day next to. You can see the whole run of dates without opening a calendar app.

  • Working with a team in Korea

    If your colleagues, clients or suppliers are in Korea, their office closes on dates that never show up in a US or EU calendar. Chuseok and Seollal each take out several working days in a row. The list tells you which days to avoid before you propose a meeting or a deadline.

  • Counting down to the next day off

    The toolbar badge shows D-7, D-3, D-1 without opening anything, and switches to D-Day in red on the morning of the holiday itself. It recalculates in the background, so the number is right whenever you happen to look at it.

How to use it

  1. 01Install Holiday D-day — the toolbar badge starts showing the countdown immediately.
  2. 02Click the icon to see the next holiday's name and date.
  3. 03The D-day number updates automatically every day.

Permissions & privacy

Single purpose

Holiday D-day has a single purpose: to display a D-day countdown to the next Korean public holiday in a toolbar badge and popup. It computes the number of days until the upcoming holiday, shows the holiday's name and date, and recalculates the countdown daily. No data leaves the user's device beyond retrieving public holiday information.

storageHoliday D-day uses the storage permission to cache the Korean public-holiday calendar and the user's preferences locally using chrome.storage.local. Caching the holiday data lets the countdown and toolbar badge render instantly without a network request each time, and preserves the user's settings across browser sessions. All data is stored locally and is never transmitted to any external server.
alarmsHoliday D-day uses the alarms permission to schedule a recurring daily update via chrome.alarms. A daily alarm wakes the service worker to recompute the number of days remaining until the next holiday and refresh the toolbar badge, so the D-day number is always accurate without requiring the user to open the popup. The alarm only triggers a recalculation — no personal data is accessed, stored, or transmitted.
http://apis.data.go.kr/*Runs only on http://apis.data.go.kr/*.

Holiday D-day works with a built-in / publicly available Korean holiday calendar. Your preferences are stored locally. No browsing history, page content, or personal data is collected, stored, or transmitted. It runs only the code shipped inside the package — no remote code is fetched.

Questions people ask

How do I see Korean public holidays in Chrome without opening a calendar?

Install the extension and the countdown appears as a badge on its toolbar icon straight away. The badge reads D-12 or D-Day, so the number is visible while you browse. Clicking the icon opens a popup with the upcoming holiday's name and date, and the full list of holidays remaining this year.

Where does the holiday data come from?

It comes from the Korean public data portal's holiday API (한국천문연구원 특일 정보 on data.go.kr). The extension requests the current year's dates and caches them locally, and it ships with a built-in 2026 holiday list that it falls back to if the request fails. That means the badge still shows something sensible when you are offline.

Are substitute holidays included?

Yes, if the government API publishes them. The countdown reflects whatever that API returns for the current year rather than a fixed list baked into the code, so substitute holidays and newly designated dates appear once they show up there. The extension re-checks about once an hour and on browser startup, so no manual refresh is needed.

What permissions does it need, and can it read the pages I visit?

No, it cannot read your pages. The manifest declares storage, alarms, and host access to http://apis.data.go.kr/* only — that single address is the holiday API. There is no content script, so the extension never runs on the sites you open; storage holds the cached holiday list, and alarms schedules the recalculation.

Does it show holidays for other countries?

No. It covers South Korean public holidays only, and the popup labels and holiday names are written in Korean. If you need a countdown to US, Japanese or European holidays, this is not the right tool. It is built for people who plan around the Korean calendar.

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