D-Day Countdown

D-Day Share Card Guide

Step-by-step: build a countdown, pick a theme, and share on Instagram, X, Facebook, Reddit, or KakaoTalk.

1. Quick start

  1. On the home page, enter an event title and a target date.
  2. Pick a theme from 7 presets: Wedding, Graduation, Exam, Birthday, Travel, K-pop Comeback, or General.
  3. The preview on the right updates in real time (every second).
  4. Click “Instagram Story (1080×1350)” to download the image.

2. The three export sizes

  • 1080 × 1350 — Instagram Story / Reels cover (the preferred 4:5 aspect).
  • 1200 × 1200 — Instagram feed, KakaoTalk card, and Facebook square posts.
  • 1200 × 630 — X (Twitter) summary card, Facebook link share, and Open Graph standard.

3. Shareable pre-filled URL

Your title, date, and theme are encoded into the URL, so sharing the link alone lets anyone open the exact same countdown.

https://dday.bal.pe.kr/?title=Finals%20D-Day&date=2026-11-13&theme=exam

4. Sharing to Instagram Story

  1. Tap “Instagram Story” in the share row — a 1080×1350 PNG downloads.
  2. Open Instagram, start a Story, and choose the downloaded image from the gallery.
  3. Add a link sticker with your pre-filled URL so followers can open the same card — that drives the viral loop.

5. X / Facebook / Reddit share

Each button opens the platform's native share dialog. The link preview defaults to the site OG image; for a custom per-event card, download the 1200×630 size and attach it directly to the post.

6. KakaoTalk share

Opens the Kakao Story share endpoint. For direct KakaoTalk DM, download the 1080×1350 PNG and attach it in chat — the most reliable path.

7. Reverse-count milestones

Auto-computed calendar dates for 5 default milestones (100, 30, 7, 1 days before, and D-Day). Use them to anchor preparation events — a 100-day wedding party, D-30 study group, etc.

8. Privacy

All inputs are stored in your browser's localStorage only — never sent to any server. Cards are rendered locally via the Canvas API.

Create a countdown