A Chrome extension that tracks your deck, graveyard, banished pile, and opponent reveals while you duel on Duelingbook.
The short version: 43Tracker reads the duel you're already playing and keeps a running count on your screen. Nothing it reads ever leaves your device. There is no account, no analytics, and no server operated by 43Tracker.
43Tracker is a side-panel extension for duelingbook.com. Its single purpose is live duel tracking: while you play, it reads the game state already rendered in your browser — your remaining deck, graveyard, and banished cards, sorted by Monster / Spell / Trap — and displays a running count. It also lets you import a decklist for comparison and log opponent cards revealed during the match (for example, by Trap Dustshoot).
To do this, 43Tracker's content scripts read card names and counts directly out of the Duelingbook page you're viewing — the same information already visible to you on screen. Chrome classifies this as website content, which is why this policy exists. It does not read your Duelingbook password, your messages, or any part of the page unrelated to the duel in progress.
An optional Shuffle Hand Hotkey setting works on the same principle. While it's turned on, 43Tracker checks each key press against the single key you've chosen, to decide whether to click a button for you. That check happens in memory and is discarded immediately. No key press is ever stored, logged, or sent anywhere, and the setting is off unless you turn it on.
Everything 43Tracker reads is written to chrome.storage.local — Chrome's on-device storage for extensions. It stays on your machine, moving only between the extension's own scripts and its side panel, so the panel can display it. It is cleared automatically when a new duel starts, and entirely when you remove the extension.
43Tracker fetches public card metadata — names and images, not personal data — from the YGOPRODeck API (db.ygoprodeck.com) to display cards in an imported decklist. No duel data, hand contents, or identifying information is sent as part of that request.
Using Chrome's own data-usage categories, here's exactly what 43Tracker touches:
| Data category | Collected |
|---|---|
| Website content (duel state: card names & counts) | ● used, on‑device only |
| Personally identifiable information | ✕ not collected |
| Health information | ✕ not collected |
| Financial & payment information | ✕ not collected |
| Authentication data (passwords, PINs) | ✕ not collected |
| Personal communications | ✕ not collected |
| Location | ✕ not collected |
| Web browsing history | ✕ not collected |
| User activity (keystrokes, for the optional hotkey) | ● checked in memory only, never stored |
Since everything lives in local browser storage, clearing it is entirely in your hands: it resets automatically at the start of each new duel, or you can remove all of it at once by uninstalling the extension from chrome://extensions.
If 43Tracker's data practices change, this page will be updated and the extension's Chrome Web Store listing will reflect the new effective date above.
Questions about this policy or how 43Tracker works can be sent to 43kostadinov@gmail.com.