Collectibles · iOS

The Flex Pile

A digital binder with collection tools and a game where cards from different TCGs can compete in the same arena.

Visit theflexpile.com ← All apps

The binder view shows the collection, its value, and the cards inside it.

Why it exists

I wanted to do something with the cards after adding them

The Flex Pile started as a way to keep a trading card collection in a digital binder. I grew up playing Magic, Yu-Gi-Oh!, and Pokémon, so I also wanted cards from different games to interact inside one app.

That led to the arena, where people can challenge cards across TCGs. A Yu-Gi-Oh! card and a Pokémon card can enter the same game even though their original rules have nothing in common.

How it works

Build the binder, then take it into the arena

Card recognition. Scan a card and the app uses image recognition to help identify it.
Collection tracking. Your whole pile organized digitally: what you have, where it lives, what it's worth.
Cross-TCG arena. Challenge cards from different games inside a shared set of rules.
Collection value. Keep market pricing with the cards in the binder and see how the collection changes over time.

Stack

What it's built on

React Tailwind Supabase Node.js Vercel Gemini (vision)

What I worked through

Two problems needed more care than I expected

A fun app, two genuinely hard problems.

Vision models are confidently wrong

Trading card games have thousands of near-identical cards, reprints across sets, and alternate versions that share artwork. The image model could identify a card with confidence and still pick the wrong printing.

I changed the flow so the model's answer could be checked before it became part of the collection. That made correction part of the workflow.

Pricing data is a moving target

The same card can map to several listings based on printing and edition, and the market changes over time. The app has to match the physical card to the right listing before the price can be useful.

More from Idunn Studio

The Flex Pile is one of three products I'm actively building around cards, collecting, and low-pressure play.

See the other apps