Online Card Shop With Inventory Sync: How It Works
An online card shop with inventory sync keeps one count across your store, eBay, Shopify and card show sales. What syncs, what doesn't, and what to check.
An online card shop with inventory sync is a branded storefront that runs on the same inventory as everywhere else you sell, so when a card sells in one place, the count drops everywhere. On InVelocity, your own store (with Stripe checkout), two-way eBay sync, Shopify sync, and card show sales through the point of sale all draw from one inventory record. TCGplayer is the exception: it's a TCGplayer-compatible CSV export, not live sync. Onboarding is by consultation right now, so it's worth knowing exactly what syncs, and how, before you book the call.
Last updated: September 2026
Why the three-tab workflow is running out of road
Most dealers start the same way. A spreadsheet, an eBay tab, maybe a Shopify tab, and a cash box at shows. It works fine at a few hundred cards and one or two channels.
Then you add a channel. Every one you add is another place a sold card can still look available, and the math doesn't grow in a straight line. Two channels means one pair of counts to keep honest. Four channels means six.
I think the dealers who set up a single synced inventory before they open their own store will have a much easier year than the ones who bolt a storefront onto the tab system. A shop without sync isn't a fourth channel. It's a fourth chance to sell the same Charizard, the same Sheoldred, or the same Blue-Eyes twice, then refund the buyer and eat the fees.
What actually syncs, channel by channel
This is the part to get exact, because "multi-channel" means different things on different platforms.
| Channel | How it connects | What moves |
|---|---|---|
| Your storefront | Built in, with Stripe checkout | Inventory deducted automatically at checkout; the new quantity pushes across connected marketplaces |
| eBay | Two-way sync | Listings, prices and quantities out; orders and sales back in; Best Offers; auto-relist when a sold-out item is restocked |
| Shopify | Sync with webhook-driven updates | Products, order import, quantity sync across platforms after a sale |
| Card shows | Point of sale | In-person sales against the same stock, plus customer records, store credit, tax and receipts |
| TCGplayer | CSV export | TCGplayer-compatible file for cross-listing and migration. No live two-way sync |
Your storefront lives at invelocity.app/shop/your-store, branded with your logo, banner, accent color and announcement banners. Customers browse your stock, add to cart, choose shipping or pickup, and pay through Stripe. They can also save cards to a wishlist and come back later.
The TCGplayer row deserves a second look. If you list there, a card that sells at a show will still show as available on TCGplayer until you re-upload the CSV. That's workable. You just have to plan for it, especially on your fastest movers.
Sync timing is where the fine print lives
"Real-time" gets used loosely in this category, so here's the honest version. InVelocity's eBay and Shopify sync is built to be real-time, but every marketplace has its own API, its own notification system and its own quirks. eBay Best Offers, for example, arrive in real time through eBay Platform Notifications, with a 6-hour reconciliation sync as a fallback in case a notification is missed.
A fallback like that exists because notifications sometimes don't arrive. If a platform tells you sync is instant with no backstop, ask what happens when it isn't.
At shows, the question is connectivity. Convention hall wifi is famously unreliable, and a cell signal behind a table of steel racks isn't much better. InVelocity's POS needs an internet connection; if it drops mid-payment, you retry the charge once you're back online. Nothing is queued to sell offline, so plan venue Wi-Fi or a hotspot for show weekends.
Condition and grading have to survive the trip
A Near Mint copy and a Moderately Played copy of the same card aren't the same item, and neither is priced like a PSA 10. Your inventory has to keep condition, set, card number and finish attached to every copy, or the storefront ends up selling "a card" instead of the card you actually have.
InVelocity tracks condition, pricing, cost basis and margin per item, and handles singles, sealed product, graded cards and accessories in the same inventory. Graded stock is priced with Invelocity Price: nine price points per card, from ungraded up through PSA 10, BGS 10, CGC 10 and SGC 10, synced daily across 350K+ cards. That keeps a slab from being listed off its raw market number.
One thing I'd still check with any system, this one included: how each condition maps when a listing goes out to a marketplace with its own condition scale. Buyers on different platforms read "LP" differently, and that's where returns come from.
Not just Pokémon
Plenty of storefront advice assumes you sell one game. Most dealers don't. InVelocity's card identification supports 25+ TCGs, including Pokémon, Magic: The Gathering, Yu-Gi-Oh!, Lorcana and One Piece. Photograph a card and it comes back with name, set, variant, finish, rarity and market price, which matters when a Magic reprint and its original printing sit side by side in the same box. For a game-specific view, see MTG card inventory, and for the multi-game side of stock management, Card Games Inventory Management for Dealers.
The fees change by channel
Sync doesn't make every sale cost the same. On your own storefront, Stripe's processing fees apply to each order, plus a 0.5% InVelocity platform fee on storefront sales specifically. Sales on a marketplace or at a show through the POS aren't charged that platform fee, but eBay and other marketplaces charge their own. Your margin on the same card really does depend on where it sells, which is one more reason to see all of it in one place.
Where InVelocity stands right now
Plain answer: InVelocity is onboarding dealers by consultation only. The dealer app isn't open for self-serve signup, and its features are listed as coming soon until it reopens. So you can't sign up tonight and connect eBay by morning. What you can do is bring your real inventory, your channels and your show schedule to a consultation and see how they map.
If you're still at the planning stage, How to Create an Online Card Shop covers setup from scratch, and Best Online Store for Trading Card Sellers compares the main options side by side.
Frequently asked questions
Does InVelocity sync with TCGplayer?
Not live. InVelocity exports inventory in a TCGplayer-compatible CSV format for cross-listing and migration. Live two-way sync covers eBay, Shopify has its own product and quantity sync, and your storefront and point of sale draw from the same inventory. A TCGplayer listing catches up when you re-upload the CSV, not automatically, so plan quantities there with that gap in mind.
What happens to my other listings when a card sells on my own storefront?
Checkout runs through Stripe, the item is deducted from inventory automatically, and the new quantity pushes across your connected marketplaces. You don't adjust eBay or Shopify by hand. Storefront orders carry Stripe's processing fees plus a 0.5% InVelocity platform fee; marketplace and in-person POS sales aren't charged that platform fee.
Does it work for games other than Pokémon?
Yes. Card identification supports 25+ TCGs, including Magic: The Gathering, Yu-Gi-Oh!, Lorcana and One Piece, and inventory handles singles, sealed product, graded cards and accessories side by side. So a multi-game dealer runs one inventory and one storefront rather than a separate system for each game they carry.
Can I sign up for InVelocity today?
Not through self-serve signup. InVelocity is onboarding dealers by consultation only right now, and the dealer app isn't open for self-serve use. The way to get started is to request a consultation, bring your actual inventory and channels, and walk through how your eBay, Shopify, storefront and show sales would map to one inventory.
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