- Multi-channel selling without real-time sync leads to overselling on at least one channel.
- Webhook-based sync updates stock across channels in seconds, not on a nightly batch.
- A single inventory source of truth prevents each channel from drifting out of agreement.
- Marketplace-specific rules (holds, reserved stock) need to be handled explicitly.
Overselling is the direct cost of poor sync
Selling the same physical inventory across multiple channels without real-time synchronization inevitably leads to overselling on at least one of them — a sale accepted for stock that's already been sold elsewhere, which costs a refund, an apology, and often a damaged customer relationship.
Webhooks beat nightly batch syncs
A nightly inventory sync means stock counts across channels can be wrong for most of the day. Webhook-driven, real-time sync updates every connected channel within seconds of a sale, closing the window where overselling can happen.
One source of truth, every channel reads from it
The most reliable pattern treats one system — often the core inventory management platform — as the single source of truth, with every sales channel treated as a synced read of it, rather than each channel maintaining its own independent count that can drift.
Marketplace-specific rules need explicit handling
Different marketplaces have different rules around reserved stock, holds during a return window, and fulfillment methods. A proper integration accounts for these channel-specific rules explicitly, rather than assuming inventory logic is identical everywhere it's sold.