The deep technical guide to how WarpWare keeps stock levels accurate across every warehouse and sales channel in real time.
Warehouse polls stock
SKU lookup + routing
Channel queues update
WarpWare polls each warehouse connector for current stock levels on a configurable interval (default: every 5 minutes). The pull returns a list of SKU/quantity pairs from the warehouse's inventory system. Each connector implements its own pull adapter — Extensiv uses a REST endpoint, ShipBob uses its fulfillment API, and custom warehouses can push stock via the Partner API instead.
Each SKU from the warehouse is resolved to a master product. The lookup first checks extensiv_sku (or the warehouse-specific SKU field), then falls back to the product's primary sku. Once matched, channel routing uses product_platform_links to determine which platform items need quantity updates.
For each channel with a platform link, the calculated quantity is enqueued into a channel-specific push queue. Platform updaters process these queues asynchronously — Shopify uses the Inventory Levels API, Amazon uses the Feeds API, WooCommerce uses REST product updates. Queues are rate-limited per platform to avoid API throttling.
WarpWare does not wait for the next warehouse poll to update channel quantities. When an order is ingested, the system immediately decrements the local available count for each SKU in the order and queues a push to all linked channels. This ensures stock is reduced on Shopify, Amazon, and other platforms within seconds of order creation — not minutes.
The next warehouse poll then reconciles the local count with the actual warehouse quantity, correcting for any manual adjustments, returns, or external changes that occurred between polls.
How it works: Order arrives → decrement local stock → queue push to all channels → warehouse poll reconciles every 5 min. The combination of instant decrement + periodic reconciliation provides both speed and accuracy.
Before pushing a quantity to any channel, WarpWare applies a three-layer buffer stack. Buffers prevent overselling by holding back units from the advertised available count.
channel_qty = max(0, available - product_buffer - source_buffer - channel_buffer)
Example: Warehouse has 100 units. Product buffer is 5, source buffer is 0, Shopify channel buffer is 10. Shopify sees max(0, 100 - 5 - 0 - 10) = 85 units.
The /inventory/sources page shows all configured inventory sources — each representing a warehouse or fulfillment connection that provides stock data. Every source has a sync direction and optional primary designation.
WarpWare polls the source for stock levels on a schedule. Used for Extensiv, ShipBob, ShipHero.
The external system pushes stock updates to WarpWare via the Partner API. Used for custom warehouses.
Both pull and push are active. WarpWare polls on schedule and also accepts real-time pushes. Used for Extensiv.
The primary source flag determines which warehouse's stock is used as the base for channel pushes when multiple sources carry the same SKU. Only one source can be primary per product.
The /inventory/compare page provides a side-by-side view of SKU overlap between any two sources — typically Shopify and the primary warehouse. This helps identify:
Overselling is the most critical failure mode in multi-channel commerce. WarpWare uses a layered defense to minimize the window where stock can be sold beyond availability.
Stock is reduced locally the moment an order is ingested — not when the warehouse confirms. This closes the gap between order placement and channel update.
Product, source, and channel buffers provide safety margin. Even if a decrement is delayed, the buffer prevents selling the last units.
Warehouse polls every 5 minutes correct any drift from manual adjustments, returns, or external systems updating stock directly.
Channel updates are processed asynchronously with per-platform rate limiting. Shopify, Amazon, and other channels each have their own queue to avoid cascading delays.
Full bidirectional sync via REST API
Inventory pull via fulfillment API
Stock levels via warehouse API
Custom warehouses push stock via REST
Reach out to connect your warehouses, or explore the rest of the documentation.