CardTrader Integration Overview

CardTrader is a European trading card game marketplace where buyers and sellers from across the world transact. Unlike Shopify — where you run your own storefront — CardTrader is a shared marketplace. Your listings compete alongside other sellers, and CardTrader handles the checkout and payment flow. Think of it as a TCG-focused alternative to TCGPlayer, with strong coverage in MTG, One Piece, Star Wars Unlimited, Riftbound, and more.

Sideboard’s CardTrader integration lets you list your in-stock inventory on CardTrader and automatically keep your Sideboard inventory in sync when orders come in — without managing two separate systems.

What the integration does

Lists your inventory on CardTrader

When you connect and push products, Sideboard sends your in-stock cards to CardTrader as individual product listings. Each listing represents one card at one condition, finish, and language — the same granularity you track in Sideboard.

CardTrader has its own product catalog, built around what they call blueprints. Every unique card printing is a blueprint. When Sideboard lists your inventory on CardTrader, it finds the right blueprint for each card you have in stock and creates a listing under it. Buyers searching for that card see your listing alongside other sellers’.

Keeps your inventory in sync after sales

When a buyer purchases your card on CardTrader, CardTrader sends an order notification to Sideboard. Sideboard’s sync engine decrements the sold item from your Sideboard inventory — the same inventory that feeds your Shopify store and your in-store point of sale. You never need to manually mark items as sold in multiple places.

If the same item also has a listing on Shopify, Sideboard updates the Shopify quantity too, automatically.

Runs a daily reconciliation

Because CardTrader does not provide real-time inventory webhooks (unlike Shopify), Sideboard runs a nightly reconciliation against your CardTrader listings. This compares what CardTrader shows as your quantities against what Sideboard knows you have, and pushes corrections. Sideboard is always the source of truth.

How CardTrader’s blueprint system works

This is the concept that takes a few minutes to understand, and it’s worth understanding before you set up the integration.

On your own Shopify store, Sideboard creates products with its own database and manages everything. If a product doesn’t exist, Sideboard creates it.

On CardTrader, Sideboard cannot create new card records — CardTrader already has a complete global catalog of cards (blueprints). To list your copy of “Black Lotus” from Alpha, Sideboard has to find CardTrader’s existing blueprint for that card and attach your listing to it.

Sideboard does this matching automatically using cross-reference IDs:

• For MTG, it matches via the card’s Scryfall ID (88% of cards matched automatically).
• For all games, it also uses TCGPlayer IDs from Sideboard’s catalog data (SWU 99%, One Piece 85%, Riftbound 71%).
• As a fallback, it matches by card name + set code + collector number.

The matching runs platform-wide on Sideboard’s side — not per-store. You don’t wait for your account to build its own blueprint database; Sideboard maintains a shared index updated daily.

For cards where automatic matching doesn’t work (a small percentage, especially for Riftbound), the CardTrader settings page shows you which cards are unmatched and lets you link them manually.

How orders work

CardTrader orders are processed via two complementary paths: webhooks and polling.

Webhooks are the primary path. When an order is placed on CardTrader, CardTrader sends an instant notification to Sideboard. Sideboard finds the matching inventory items and decrements them. The update also propagates to your Shopify listing if you have Shopify connected.

Order polling is the backup. Every 15 minutes, Sideboard also polls CardTrader’s orders API to check for any orders that might have been missed by a webhook failure. If an order has already been processed (via webhook), the polling skips it — no double-counting.

CardTrader Zero orders

CardTrader has a bulk-listing program called CardTrader Zero. If you participate, orders from that program behave slightly differently: the inventory decrement happens when the order enters a pending state (rather than when it’s fully paid), because CardTrader guarantees payment. Sideboard handles this distinction automatically.

Cancellations

If a CardTrader order is canceled, Sideboard restores the inventory. The restored quantity is pushed back to Shopify as well so all your channels stay accurate.

Oversell protection

Because CardTrader does not reserve inventory when a buyer adds items to their cart (unlike Shopify, which holds stock), there’s a window where the same card could sell on CardTrader and through another channel simultaneously.

Sideboard addresses this with a quantity buffer. By default, Sideboard holds back 1 unit from the quantity it reports to CardTrader for every listing. So if you have 2 copies of a card, CardTrader sees 1; if you have 10, CardTrader sees 9. This reduces the chance of an oversell across channels.

You can adjust the buffer (0 to 5) or turn it off entirely from the CardTrader settings page.

Authentication: API token, not OAuth

Unlike the Shopify integration, CardTrader uses a simple static API token rather than OAuth. You generate a token in your CardTrader account settings and paste it into Sideboard. Sideboard validates the token immediately and stores it securely.

The token does not expire on a schedule, but if you revoke it from your CardTrader account or generate a new one, you’ll need to update it in Sideboard.

Supported games

The CardTrader integration currently supports the following games:

• Magic: The Gathering
• One Piece Card Game
• Star Wars Unlimited
• Riftbound

Support for additional games (Pokémon, Yu-Gi-Oh!, Gundam, Lorcana) is planned for a future release.

What the integration does not do (yet)

• Sealed products (booster boxes, bundles, precons) — singles only in the current version.
• Automatic pricing adjustments based on CardTrader market data — prices pushed to CardTrader are your prices from Sideboard. You control your pricing.
• Order fulfillment — Sideboard tracks orders but does not handle the actual shipping or label creation.

What’s next

• Set up the integration: CardTrader Setup
• Managing inventory in Sideboard: Managing Inventory
• How presale works across channels: Presale
• Shopify integration: Shopify Overview

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