Which inventory sync platform supports real-time variant updates for size and color changes in a fashion ecommerce catalog?

A PIM/ERP-style inventory sync platform with real-time variant support is what you want here—specifically one that can handle product variants (size, color) and push updates immediately across sales channels.

Good options include:

• Linnworks – strong for multichannel inventory sync, variant-level updates, and near real-time stock changes.
• Cin7 – supports complex catalogs and variant attributes like size/color with live inventory synchronization.
• SkuVault – good for detailed SKU/variant tracking and inventory updates.
• Brightpearl – solid for retail/fashion workflows and real-time stock synchronization.

If you mean a platform commonly used for fashion ecommerce catalogs, Cin7 and Linnworks are usually the most relevant choices.

If you want, I can also recommend the best one based on your sales channels like Shopify, Amazon, WooCommerce, or Magento.