Amazon Buy Box tracker: see who wins the Buy Box, and when

The Buy Box is the Add to Cart button — Amazon’s own name for it is the Featured Offer — and by every account we have seen the seller holding it takes the large majority of a listing’s sales, although Amazon publishes no figure. It is also history you cannot go back and read: Amazon shows you today’s winner and nothing else, so a Buy Box you lost on Tuesday and regained on Thursday leaves no trace you can point at. The AMZ Selling Tools Buy Box tracker reads the live listing once a day and writes down who held the Buy Box on the day of the check, at what price, and with which other sellers alongside it.

What is recorded on every check

• Buy Box — the name of the seller winning the featured offer.
• Seller 1, Seller 2, Seller 3 — the top three offers on the listing by name. Three is the limit: the tracker never invents a fourth.
• S1–S3 Type — each of those sellers’ fulfilment type, recorded as Amazon, FBA or FBM.
• S1–S3 Condition and Price — the item condition each is selling and the price they are asking, so you can see how far under you a rival sits.
• Offers Count — how many other offers Amazon shows in the “Other sellers on Amazon” panel. Empty on a single-seller listing, where that panel does not appear at all.
• Ships From — who actually dispatches the Buy Box offer, which is often Amazon even when the seller is not.
• S&S Seller — the seller holding the Subscribe & Save box, which is not always the same one, alongside the S&S price.

All of it lands in the same row as the price, the deal and coupon flags, the stock wording, the delivery promise and the rank — so a lost Buy Box arrives with its own context rather than as an isolated fact.

Why the Buy Box rotates

Amazon does not publish how the featured offer is chosen, so what follows is what sellers commonly observe rather than a documented rule. Landed price — the item plus delivery — clearly matters, and so does fulfilment: offers dispatched by Amazon appear to be favoured over merchant-fulfilled ones at a similar price. Delivery speed to the individual shopper, stock depth and a seller’s own performance record are widely believed to play a part. On a listing where several sellers are close, the winner can change several times a day; where one offer dominates, it can hold for weeks. Nobody outside Amazon can predict it, which is exactly why the useful thing is a record of what actually happened.

One case is worth stating plainly: sometimes the page carries no featured offer at all — the item is out of stock, or delivery to that location is restricted. There is then no winner to record, and the Buy Box column is left empty rather than filled in, so the gap itself becomes part of the history.

The Buy Box you see depends on where the shopper is

Amazon builds the product page for the shopper’s location, and delivery is part of how the featured offer is chosen — so a seller shipping from Texas can plausibly win in Dallas and lose in New York on the same afternoon. A tracker that checks from one place can only ever show you one answer.

The United States is checked from Brooklyn, Chicago, Dallas, Los Angeles, Denver and Miami Beach, and Canada from Toronto, Ottawa, Montreal, Calgary, Edmonton and Vancouver. The United Kingdom, Germany, France, Italy, Spain, Poland, Sweden, the Netherlands, Belgium and Australia are each checked from one location in-country — 22 locations across the 12 marketplaces. Each ASIN-and-location pair is its own tracked row, so add the same ASIN in three cities and you get three rows side by side, each checked daily, each costing the same flat rate.

Alerts when the winner changes

The Buy Box column is a text field, so it takes four conditions: changed, becomes, contains and stops containing.

• “Buy Box changed” — the ready-made preset. Any turnover on that listing, whoever is involved.
• “Buy Box stops containing” your store name — the narrower version: it only emails you when you personally lose it.
• “Offers Count increased” or “Offers Count rises above 3” — competition on the listing is growing, whether or not the Buy Box has moved yet.
• “Seller 1 changed”, or a price condition such as “S1 Price drops below” — the top offer has been undercut.

Emails arrive after every check, or as one daily summary once the day’s last scheduled check has finished. Two honest limits are worth knowing before you rely on them. First, a rule compares one value with the previous one, so a seller slot filling in for the very first time is written to the history rather than emailed — which is precisely the moment a new seller arrives on a quiet listing. Second, there is no dedicated “hijacker alert” here, because Amazon exposes nothing that reliably identifies one; what exists is the record of who is on the listing and who holds the Buy Box, and alerts on those changing. The fulfilment type and item condition columns are compared check-to-check and exported, but they are not among the fields you can raise an alert on.

Reading the rotation over time

The table shows the latest check by default. Four controls turn it into a history:

• Click a Buy Box cell for a dated timeline of every winner ever recorded on that row, with the timestamp of each check.
• Changes narrows the table to listings where something moved since the previous check — 80 fields are compared, seller names, types, conditions and prices among them.
• Diff View highlights the old value against the new one, so a switch from your store to a reseller reads at a glance.
• All Data lists every past check as its own row, and the date picker rewinds the whole table to how it stood on a chosen day.

Over a few weeks that record answers the questions Amazon will not: what share of days you held the Buy Box, which competitor takes it and at what price, whether you lose it in one city before the others, and whether a price change of your own actually bought the share back.

Export and price

Download the Buy Box and seller columns to CSV or TSV, pull them into Google Sheets with one copied Apps Script so the sheet refreshes itself, or read them through the personal read-only API — all included, on every plan, with no add-on.

Tracking costs a flat $0.10 per ASIN per month, which buys 30 daily checks of all 92 columns; 50 ASINs is $5.00 a month. Every new account starts with a free 30-day trial of up to 10 products and 10 checks a day, with no card required.

For the background — what the Buy Box is, what Amazon is understood to weigh and why it moves — read our guide to who wins the Amazon Buy Box and why it changes. To watch the rest of the page alongside the offer, see listing monitoring; for the demand signal beside it, the BSR tracker.