Amazon Stock & Buy Box Alert: Know the Moment You Lose the Buy Box

Give it a list of ASINs and it tells you who owns the buy box on each one, who the order ships from, how many other offers exist and whether the item is in stock. Run it again and it tells you what changed: who took the box, what sold out and what came back.

Built for Amazon sellers and brand owners who find out they lost the buy box from a sales dip, days after it happened.

How it works

flowchart LR
    A["ASINs or product URLs"] --> B["Render each product page<br/>(residential proxy, pinned country)"]
    B --> C["Buy box seller,<br/>ships from, offers, stock"]
    C --> D{"Compare with<br/>last run"}
    D -->|new seller| E["buybox-changed"]
    D -->|now unavailable| F["went out of stock"]
    D -->|now available| G["back in stock"]
    D -->|price moved| H["price-drop / price-rise"]
    E --> I[("Alert rows")]
    F --> I
    G --> I
    H --> I

The proxy exit country is pinned to the marketplace you chose. Without that, Amazon localises the buy box to wherever the proxy lands, and a .com page comes back showing a European seller at a euro price.

Built for

• Amazon sellers who need to know within hours, not weeks, that a rival took the box
• Brand owners watching unauthorised resellers appear on their own ASINs
• Repricing teams measuring how often each competitor holds the box
• Buyers and sourcers watching for restocks on items that keep selling out

Input

{
  "asins": ["B0FGJF172R", "B0FGJCYQKK"],
  "marketplace": "US",
  "onlyChanged": true
}

Setting	What it does
asins	Bare ASINs or full Amazon product URLs, mixed freely
marketplace	Which Amazon site to read: US, UK, DE, JP and 11 more
onlyChanged	Return only buy box changes, stock flips and price moves
onlyThirdPartyBuyBox	Only listings a third party has taken from Amazon
onlyAmazonBuyBox	Only listings Amazon itself is selling
onlyOutOfStock / onlyLowStock	Spot rivals who have sold out or are about to

Output

{
  "asin": "B0FGJF172R",
  "title": "Zojirushi SM-VH72-AZ GoCafe Insulated Stainless Steel Mug",
  "brand": "Zojirushi",
  "buyBoxSeller": "Pattern Home",
  "buyBoxSellerType": "third-party",
  "shipsFrom": "Amazon",
  "hasBuyBox": true,
  "offerCount": 7,
  "price": 28.99,
  "currency": "$",
  "inStock": true,
  "lowStock": false,
  "previousBuyBoxSeller": "Amazon.com",
  "buyBoxChanged": true,
  "changeType": "buybox-changed",
  "url": "https://www.amazon.com/dp/B0FGJF172R",
  "checkedAt": "2026-09-15T18:20:04.881Z"
}

changeType is the field to filter on. It is one of buybox-changed, went-out-of-stock, back-in-stock, price-drop, price-rise, new, unchanged or first-run.

Turn it into an alert

Set onlyChanged to true and schedule it hourly on your own ASINs. The first run records who holds each box. Every run after that returns only the listings where something actually moved.

{
  "asins": ["B0FGJF172R", "B0FGJCYQKK", "B0FGJFWHH4"],
  "onlyChanged": true,
  "onlyThirdPartyBuyBox": true
}

Run it as an API

curl -X POST "https://api.apify.com/v2/acts/arched_friend~amazon-buybox-alert/run-sync-get-dataset-items?token=YOUR_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "asins": ["B0FGJF172R"],
    "marketplace": "US",
    "onlyChanged": true
  }'

Pricing

You pay $0.01 for each product actually read. Retries are free, and a quiet run costs the same as a noisy one.

Watching 30 ASINs hourly	Monthly cost
Checking by hand	not realistically possible
Most buy box monitoring suites	$99 to $500 per month
This Actor	around $216 per month, or $7 per month once a day

Common questions

Why does a seller show as third-party when it is my own brand? buyBoxSellerType describes Amazon versus anyone else, not authorised versus unauthorised. Your own seller account is a third party in Amazon's terms.

What if there is no buy box at all? hasBuyBox comes back false and buyBoxSeller is null, which is itself worth alerting on: a suppressed buy box usually means a pricing or listing problem.

Does a missing seller trigger a false alert? No. A buy box change is only reported when both the old and the new seller were actually read, so a page that fails to render the seller row stays quiet.

Can it list every offer on a listing? It reports the offer count and the winning seller. Reading the full offer list for every ASIN is a much heavier crawl and a different product.

Related products

• Amazon Price Tracker to follow the price on the same ASINs over time
• Amazon Deals & Coupon Monitor to catch coupons and lightning deals
• eBay Price Tracker to see what the same product sells for on eBay
• Multi-Store Stock Alert to chain Amazon, eBay and Shopify into one feed
• Shopify Price Tracker to watch the same brands on their own storefronts