Multichannel inventory
Sell cards on multiple marketplaces from one inventory
Organise your TCG inventory for CardTrader and Spellstrade: identify variants, manage quantities and check synchronisation before adding a sales channel.
Updated September 30, 2026
The short answer
To sell the same cards on CardTrader and Spellstrade, connect both channels to Cardunity and use one central inventory for each variant. Three physical copies remain three: after one sells, the remaining availability to synchronise is two. Always check the synchronisation result.
You have a card available and want to reach customers who shop on different marketplaces. The starting point is simple: that card is still one physical copy, even when it appears in two listings. Your job is to keep availability, attributes and sales aligned.
This guide offers a method for preparing inventory, connecting channels and checking the first update. The numbers are illustrative: they do not describe sales results or guaranteed synchronisation times.
Identify the variant before the quantity
Two cards with the same name are not necessarily the same product. Set, collector number, language, condition and finish can change the variant. A graded or serial-numbered card also needs to be distinguished from a standard copy: a shared name is not enough to combine quantities.
Before importing, check a small sample of cards. An Italian Near Mint Pokémon card and the same print in Japanese Played condition must remain distinguishable. Merging those rows could lead to an order for a version you do not own.
Count physical copies only once
Imagine owning three copies of one variant. Listing them on two channels does not give you six cards. The reference remains the central inventory of three copies; after one sale, the remaining quantity to synchronise is two.
If you import listings that already exist on several marketplaces, check that they represent the same inventory before linking them. Do not automatically add together quantities that describe the same cards on your shelf.
| Event | Central inventory |
|---|---|
| You import three copies of one variant | 3 copies available |
| You also list them on the second channel | Still 3, not 6 |
| You sell one copy on either channel | 2 copies to synchronise across channels |
Check the second channel before expanding
In Cardunity, connect marketplaces through Channels and manage products in Stock. Start with a few easy-to-identify products, check the channel's required information and review the publishing result.
Open the listing on the destination marketplace and compare the variant, quantity and price. This is especially useful when bringing inventory already on CardTrader to Spellstrade. Expand your selection once you have checked the connection.
Synchronisation needs monitoring
Updates pass through different services and can be queued or fail. Do not assume a submitted change is already visible on every marketplace: check channel status and any errors before correcting quantities elsewhere.
If you also sell at a shop counter or an event, record those sales in the central inventory. Synchronisation can only update sales and changes the system knows about. For highly sought-after single copies, consider exposure across channels carefully.
A short check before expanding your inventory
Use this checklist when adding a marketplace or changing how you manage copies. Reliable data comes first; the opportunity for more sales comes from exposing that inventory to different audiences.
- Correct variant: set, collector number, language, condition and finish.
- Quantity matches the copies actually available.
- Listing price and content checked on the channel.
- Synchronisation completed or any error resolved.
- A clear process for offline sales and inventory corrections.