Why I built Karto

I built Karto because of card shows.

If you've been to a convention, you know how it goes. Queue for a vendor's table. Flip through binders while people wait behind you. Walk away without the card you came for, not because they didn't have it, but because hunting through physical stock is slow and awkward for everyone.

Vendors get the other half of that mess. Prices live on stickers. Inventory lives in binders, slabs, and boxes under the table. Someone asks for a card that might be in the second case, or already sold, or still in the car. And if you're collecting on the side, good luck remembering what you actually paid for any of it.

I wanted something plain: put the stock online with asking prices, share a link or QR, and let people browse before they reach the table. Less queue friction. Less peeling and reprinting stickers. A clearer sense of cost, sales, and whether you're even making money.

So I spent a weekend and built Karto. Catalog cards (raw, slabs, sealed), set sticker prices, log what you paid, mark things sold, and see profit over time. Same page is your public storefront when you're ready.

Open source

If you want to fork it or run your own version:

• Source: github.com/kevicebryan/Karto
• Docs: karto.kevbry.in/docs

That's the whole idea. A shareable stock list for people who sell in person and still want to know if the hobby is eating their wallet.

Contributed as Solo Dev

Solo Project

Made using Nextjs, Supabase