All systems
In Build Computer VisionMarketplacePython

Card Marketplace & Tracker

A marketplace, valuation engine and scanning toolkit for trading card resellers

SYS.01ProblemResearchSYS.02ValuationEngineSYS.03Scanner+ MarketplaceSYS.04RefinementSYS.05Product
The problem

Buying, pricing and tracking trading cards is still mostly manual: check the set, check the condition, check what similar cards actually sold for, one card at a time. At a booth or a show, with people waiting, that process is slow and the margin for costly mistakes is high.

The opportunity

Vintage WOTC-era Pokémon cards (1995–2002) are routinely undervalued by sellers who don't know what they have, and even once bought, most resellers are still tracking a growing collection's value across spreadsheets, memory and gut feel.

The solution

A single toolkit that covers the whole lifecycle of a card: a marketplace and valuation engine pulling from real sales data, a card scanner for instant condition-aware pricing, and a Quick Card tool for fast on-the-spot quotes when a seller is waiting at a booth.

Technical challenges
  • Making sure every card keeps an honest, permanent record of what it actually cost, even as it moves between a personal collection and items for resale later, so nothing gets double-counted or quietly lost track of.
  • Batch-scanning a whole binder page at once while keeping the review screen laid out exactly like the physical page, so removing a card leaves a gap rather than reshuffling everything else, keeping the digital view mapped to reality.
  • Automated QR pairing between desktop and mobile: scan a code and the two devices sync live, so a laptop's bigger screen can drive the review while a phone's camera does the actual capture, without any manual device linking.
  • Getting more out of the camera even when scanning from a laptop, rather than treating desktop as a second-class capture path compared to mobile.
  • Building in real-world trade practice rather than a simple assumption: full even swaps between sellers are rare, so cash, credit and trade-in percentages all needed to be adjustable rather than fixed.
Lessons learned

The tool that gets used at a booth has to be faster than the tool that gets used at a desk. Quick Card exists because a perfectly accurate valuation is worthless if it takes so long that a queue forms behind the seller you're quoting. The QR pairing taught me something similar from the other direction: a laptop screen is genuinely better for reviewing a big batch, but its camera shouldn't be treated as an afterthought just because a phone's is more obvious. Getting both working well together, in sync, mattered more than picking one device as the 'real' one.

Current status

Core marketplace, valuation engine and scanning tools are built and in active use. Further refinements are ongoing, personal-use-first with a clear path to becoming a standalone product.

Myo Discovery Everant Studio