The last unit of a product can appear at the same time on a website, a marketplace and a salesperson's quotation. If every channel looks only at physical or recorded stock, each believes that unit is free. The result is two confirmed orders, one item and a decision about which customer to disappoint.
Reservation prevents this only when all channels follow one availability rule. It records that a quantity has already been promised to a specific order even though the goods may remain physically on the shelf.
What a reservation changes
Available stock = usable recorded stock − active reservations − blocked quantity.
If 20 usable units are recorded, six are reserved for confirmed orders and two are blocked for inspection, 12 can be offered to new customers. A reservation is not a stock issue and does not change the total recorded quantity.
| Event | Recorded | Reserved | Available |
|---|---|---|---|
| Before the order | 20 | 0 | 20 |
| Six units confirmed | 20 | 6 | 14 |
| Two units blocked | 20 | 6 | 12 |
| Six units shipped | 14 | 0 | 12 |
Soft and firm reservations
| Type | Typical use | Main risk |
|---|---|---|
| Soft | Shopping basket, preliminary request or short payment window | An excessive expiry time hides stock from real demand |
| Firm | Confirmed, paid or accepted order | Uncontrolled manual release leaves the customer without stock |
A website basket often needs only a short soft reservation. After payment or salesperson confirmation, it becomes firm. The exact boundary is a business choice, but the same order status must affect availability consistently in every sales channel.
The reservation lifecycle
- Create. Check availability and link the reservation to the order line, item, quantity and warehouse.
- Confirm. Payment or approval changes the reservation to a guaranteed state.
- Pick. Warehouse staff select units; the reservation may be assigned to a bin, batch or serial number.
- Ship. The physical issue reduces recorded stock and closes the fulfilled reservation quantity.
- Release. Cancellation, refusal or expiry returns the unused quantity to availability.
Every transition should be idempotent: a repeated payment notification, marketplace event or button click must not create a second reservation for the same order line.
Expiry must not freeze stock forever
Unpaid orders need an expiry rule. The period depends on the payment method, stock velocity and customer promise. A scarce retail item may be held for 15–30 minutes, while an agreed business invoice may justify one working day.
Before releasing stock, check the current payment state. A bank can authorise the transaction before its delayed message reaches the order system; a timer alone could otherwise release paid goods.
Partial reservation and shortages
A customer orders 10 units but only seven are available. The business can:
- reserve seven and agree a later date for the balance;
- reserve nothing until the complete quantity is available;
- reserve seven and record three as confirmed back-order demand.
The chosen policy must be visible to staff and the customer. Ten units must not be presented as ready to ship when three exist only in a purchasing plan.
What happens when an order changes
| Order change | Correct reservation action |
|---|---|
| Quantity reduced | Release the difference immediately |
| Product replaced | Secure the new item before safely releasing the old one |
| Warehouse changed | Check availability at the destination before moving the reservation |
| Order cancelled | Release the unfulfilled quantity once and record the reason |
| Partially shipped | Close the fulfilled part; retain or deliberately release the remainder |
Reservation controls
- One authoritative available-stock figure for the website, marketplaces and sales team.
- An expired-reservations report showing the order, owner and reason.
- Role-based approval and an audit trail for manual release of firm reservations.
- Separate rules for pre-orders, inbound goods and returns.
- Availability recalculated after every relevant event, not only overnight.
- An alert when a firm reservation exists but the order does not progress to picking.
Conclusion
A reliable reservation links an item, warehouse, quantity, order, expiry and status. It does not issue stock; it honestly reduces what can be promised to new demand. Shipment converts the reservation into a physical movement, while cancellation returns it to availability.
Once reservations are controlled, the next task is to verify stock accuracy regularly without closing the whole operation. Cycle counting provides that control. Explore the Business Reactor catalogue module.
