I built my ideal TCG tracker with my Hermes agent, then open sourced it

I was trying to keep track of my TCG collection, mostly Pokémon, including a lot of Japanese cards and sealed products. Nothing too crazy at first. Just wanted to know what I had, what it was worth, and whether a trade or store offer made sense.

Then it got annoying.

Prices were scattered across different sites. Japanese prints were harder to track than they should be. Some tools were decent for one game but useless for another. And the apps that felt close to what I wanted usually had the same catch: create an account, sync your data somewhere, then pay monthly for features that felt basic.

TCGs are already an expensive hobby. I didn’t want another subscription just to manage the cards I already bought.

So I started building my own tracker with help from my agent, Nova. Nova helped get the first working version moving, and I kept shaping it around how I actually collect, trade, and sell.

It’s called Rarebox.

It’s a free, open-source TCG portfolio tracker that runs entirely in your browser.

No account.
No backend.
No subscription.
No pro tier.
Your data stays on your device.

Right now it supports live pricing for Pokémon, including Japanese sets, Magic: The Gathering, Yu-Gi-Oh!, Disney Lorcana, One Piece, and Riftbound.

You can track raw cards, sealed products, graded slabs, decks, trades, and sales.

The part I’m most excited about is Card Booth. It’s for selling at local events or shows. You can generate a QR code for your table, manage sales and trades from your phone, and leave a live-updating display QR on a tablet so buyers can browse without constantly asking what’s available.

Try it: rarebox.io

I’d love feedback from collectors, traders, and sellers.

What would Rarebox need to do for you to actually use it every day?