Acknowledging Amazon Purchase Orders: The 24 and 48 Hour Rules

When Amazon sends a vendor a purchase order, the vendor answers it within 24 hours, line by line: accepted, backordered with a new date, or rejected with a reason. Changes to quantity, price or dates can follow within 48 hours; after that only the dates can move. Any line left out of the answer counts as rejected, and the cost price confirmed has to be the cost price invoiced.

Those rules come from Amazon's own documentation for vendors, and they matter beyond the order in hand. Every answer feeds the confirmation rate Amazon measures the vendor on, and every mismatch between what was confirmed and what was shipped or invoiced comes back later as a dispute or a deduction.

Amazon's documentation for retail purchase orders asks for the acknowledgement within 24 hours, backordered items included. It can be sent through the API, through EDI, or in Vendor Central, and a vendor who cannot meet the requirements through the API is told to confirm in Vendor Central instead. What matters is that every order gets an answer inside the window.

The answer has to cover every line. Amazon's documentation is explicit that line items missing from an acknowledgement are implicitly rejected, and that an acknowledgement sent without its code is rejected too. A vendor who answers the lines it can fill and leaves the rest for later has, in Amazon's system, already said no to the rest.

Plan for the window as the documentation states it, 24 hours, rather than as a working day. An order that arrives on Friday afternoon is safest answered before the weekend, which means somebody owns the inbox, or the EDI feed, every day orders can arrive.

Accepted means the vendor will ship the confirmed quantity on the dates in the order. Backordered means the vendor will ship, on a later ship or delivery date that the acknowledgement states. Rejected means the vendor will not ship that line, and a rejection must carry a reason.

The choice is not easily undone. Amazon's documentation says a line first rejected cannot later be changed to accepted or backordered, so a rejection sent in haste is final for that order. And a vendor may not confirm more than Amazon ordered. The confirmation rate, the share of units Amazon asked for that the vendor confirmed, is built from these answers, and how it shapes future orders is in Amazon purchase orders down or stopped.

So the honest answer is the useful one. Accept what can be shipped on time, backorder what can be shipped later with a real date, and reject only what cannot be supplied at all, with the reason that is true. A vendor who accepts everything and short ships has the worst of all three: a high confirmation rate on paper and a shipment that does not match it.

Plans change after the first answer. Amazon's documentation allows an updated acknowledgement within 48 hours for any change to quantity, price, ship dates or delivery dates. After 48 hours, only ship and delivery dates are expected to change.

A late update is worse than an early correct answer, so the first answer should already be a considered one; the window is for genuine changes, such as a production run slipping or a price agreed after the order arrived, not for finishing an answer that was rushed. That makes the first two days the time to get the numbers right: check stock against every accepted line, confirm production dates for every backorder, and correct the cost on any line where it does not match the agreement. After the window, a wrong quantity or price is no longer a correction to an acknowledgement but a difference between what was promised and what arrived.

Amazon requires the cost price in the acknowledgement to match the unit cost price that is invoiced. It sounds administrative and it is where many disputes start: a cost confirmed from an old price list, or a new price agreed but not yet loaded, produces an invoice that does not match the order, and the payment that follows does not match the invoice. How those differences show up in what Amazon pays is in matching Amazon vendor payments to invoices and deductions.

Keep one source of truth for cost per item, updated the day a new cost is agreed, and acknowledge from it. If the cost on an incoming order looks wrong, correct it in the acknowledgement within the 48 hours rather than invoicing a different number later.

Vendors who ship Amazon's customer orders directly, rather than shipping stock into Amazon's network, answer a different kind of order under the same 24 hour expectation. Amazon's documentation for direct fulfilment is fill or kill: the order is accepted or rejected in its entirety, not line by line, and an item with an invalid identifier is rejected with its own code. The quantity can never exceed the order.

A vendor running both programmes needs both processes written down separately, because a team used to backordering retail lines will try to part-accept a direct fulfilment order that does not allow it. Which programme suits which brand, and how Vendor Central differs from selling yourself, is in Amazon Vendor Central vs Seller Central.

Most acknowledgement problems are not noticed on the day. They surface weeks later, when the shipment, the invoice or the payment does not match what was confirmed. The usual causes are few: lines missing from an answer and so rejected without anybody deciding it, a backorder date guessed rather than checked with production, a cost confirmed from a superseded price list, and an accepted quantity that the warehouse could not actually pick.

Each has the same root, an answer sent without a check against the source that decides it: stock for quantity, production for dates, the cost list for price. The fix is the order of work, not more speed. Check first, then answer, then verify that the answer arrived as intended.

And keep a record of every acknowledgement with what it was checked against. When a dispute arrives two months later, the vendor who can show what was confirmed, when and why, resolves it in a message; the one who cannot spends a week reconstructing it.

Read new orders twice a day, morning and afternoon, so nothing approaches the 24 hour mark. For each, check the items against stock and open production, the cost against the agreed cost list, and the dates against what the warehouse can do. Answer every line, every time, with the answer that will turn out to be true.

Then check the next day that every acknowledgement was received in the state intended; Amazon's documentation points vendors to Vendor Central to verify it, and to a case if the values shown are wrong. Track the confirmation rate weekly. A falling rate with no change in stock usually means answers are going out late or incomplete, which is a process fix rather than a supply one.

Running purchase order acknowledgement, shipments and the reconciliation behind them for vendors is part of our Amazon Vendor Central service.