CardShark
CardShark is a free Chrome extension. It has no user accounts, no payments, and no backend server: everything it does happens locally in your browser.
What CardShark does
CardShark reads the listing titles and prices on eBay search-results and listing pages you visit, looks up the corresponding card's market price from public trading-card-game price APIs, and shows a comparison badge next to the eBay price.
What data CardShark collects
None. CardShark does not collect, transmit, sell, or store any personal information, browsing history, or eBay account data. There is no server operated by CardShark that receives data from the extension. There is no backend at all.
What data CardShark reads
To do its job, the extension reads the content of eBay pages you visit (listing titles, prices, and shipping costs) purely in your browser, in order to compute a price comparison. This information is never sent anywhere except as described below; it's used locally to build the badge shown on the page.
Network requests CardShark makes
CardShark's badge feature works by looking up card prices from a small set of free, public APIs, called directly from your browser:
| Destination | Purpose |
|---|---|
| api.scryfall.com | Magic: The Gathering card & price lookups |
| api.pokemontcg.io | Pokémon card & price lookups |
| db.ygoprodeck.com | Yu-Gi-Oh! card & price lookups |
| open.er-api.com | Currency conversion for non-USD eBay listings |
These requests contain only the card name/set information needed to look up a price (derived from the public eBay listing you're viewing). No personal or account information is included, and CardShark does not read anything back from these APIs beyond the price data it displays.
CardShark also reads eBay pages (ebay.com, ebay.ca, ebay.co.uk only; CardShark does not request access to any other eBay site or any other website) in order to scrape listing titles and prices. It does not modify, submit, or interact with eBay on your behalf beyond displaying badges.
What data is stored, and where
Your settings (which TCGs are enabled, deal threshold, display preferences, etc.) are stored using Chrome's local extension storage (chrome.storage.local) on your own device. This data:
- Never leaves your browser
- Is not synced to any CardShark server (there isn't one)
- Is removed automatically if you uninstall the extension
Changes to this policy
If CardShark's data practices ever change, this document will be updated and the "Last updated" date above will reflect the change.
Contact
Questions about this policy can be sent via the support page.