What is StackKnack
TLDR
StackKnack is inventory management software built for sneaker and luxury resale businesses. It connects Shopify, StockX, eBay, and Clover POS into one real-time inventory system. It prevents oversells, tracks margins, and gives operators confidence in what is actually available to sell.
Who this is for
- Sneaker resale store owners running multiple sales channels
- Luxury resale operators managing consignment and owned inventory
- Operations managers at multi-location resale businesses
- Event vendors selling at sneaker conventions and pop-ups
What StackKnack does
StackKnack provides a single source of truth for resale inventory. It solves these specific problems:
Multi-channel inventory sync
When you sell a pair of shoes on Shopify, StackKnack automatically updates the quantity on StockX, eBay, and your in-store POS. This happens in real time. You do not need to manually update listings.
Oversell prevention
StackKnack tracks committed inventory across all channels. If an item is reserved on one platform, it is marked unavailable on others. This eliminates the problem of selling the same item twice.
Margin tracking
Every item in StackKnack has a cost basis. When it sells, StackKnack calculates the actual margin after platform fees, shipping, and other costs. You can see profitability per item, per channel, and per time period.
Consignment management
For stores that sell on consignment, StackKnack tracks which items belong to which consignors. It calculates payouts based on agreed-upon splits and generates settlement reports.
Dead stock visibility
StackKnack flags items that have not sold within configurable time windows. This helps operators identify items that need price reductions or removal from active listings.
Inputs
- Product data from Shopify, StockX, eBay, or manual entry
- Sales transactions from all connected channels
- Cost information per item (purchase price, shipping, fees)
- Consignment agreements (consignor, split percentage, terms)
Outputs
- Unified inventory counts across all channels
- Real-time sync updates to all connected platforms
- Margin reports per item, channel, and time period
- Consignment settlement reports
- Dead stock alerts
- Inventory valuation reports
Integrations
StackKnack integrates with these platforms:
| Platform | Type | Sync Direction |
|---|---|---|
| Shopify | E-commerce | Bidirectional |
| eBay | Marketplace | Bidirectional |
| StockX | Marketplace | Bidirectional |
| Clover | POS | Bidirectional |
Limitations
- StackKnack is designed for resale businesses. It is not general-purpose inventory software for manufacturing or wholesale.
- Real-time sync depends on API availability from connected platforms. If Shopify or eBay APIs experience downtime, sync may be delayed.
- StackKnack does not handle shipping logistics. It tracks inventory status, not package delivery.
- Pricing recommendations are not currently part of the product. StackKnack tracks margins but does not suggest prices.