eBay Seller Inventory Monitor

Watch any eBay seller's live listings and find out exactly what changed since the last run — new items added, prices moved up or down, and items taken down — while also getting the seller's full current inventory as clean, structured rows. Built for anyone who needs to keep a close eye on a shop over time: resellers tracking a competitor's every move, brands policing unauthorised sellers, sourcing teams spotting fresh stock the moment it goes live, and analysts building a running history of a shop's pricing and assortment. Give it a seller, put it on a schedule, and each run tells you what moved.

What you can do with it

• Track a competitor's shop — see every new listing, every price move and every takedown between runs, with the before-and-after prices already worked out.
• Get alerted to fresh stock the moment a seller lists it, so you can react to new inventory before anyone else does.
• Watch pricing over time — schedule it daily or hourly and build your own history of how a seller prices their catalogue.
• Police your brand by monitoring the sellers who carry your products and catching new listings as they appear.
• Snapshot a full inventory on demand — pull every live item a seller currently has, as one row each, for a catalogue audit or a stock count.
• Feed a dashboard with a steady stream of change events per seller, each stamped with when it was first seen and when it was detected.

What you get

Two kinds of rows. Every run outputs the seller's current inventory (one row per live item), and — from the second run onward — a change event for each thing that moved. Abridged samples.

A current-inventory row:

{
  "type": "inventory_item",
  "seller": "discountcomputerdepot",
  "marketplace": "US",
  "itemId": "336747884909",
  "title": "Columbia C300Ball USA BOWLING BALL",
  "condition": "Pre-Owned",
  "price": 49.90,
  "currency": "USD",
  "buyingFormat": "BUY_IT_NOW",
  "freeShipping": true,
  "location": "United States",
  "listedAt": "2026-08-17T16:27:00",
  "listedAtText": "Aug-17 16:27",
  "imageUrl": "https://i.ebayimg.com/images/g/abcAAOSw/s-l500.webp",
  "url": "https://www.ebay.com/itm/336747884909",
  "firstSeenAt": "2026-08-10T09:00:00.000Z",
  "capturedAt": "2026-08-18T12:00:00.000Z"
}

A change event, when a price moves:

{
  "type": "price_change",
  "seller": "discountcomputerdepot",
  "marketplace": "US",
  "itemId": "336747884909",
  "title": "Columbia C300Ball USA BOWLING BALL",
  "url": "https://www.ebay.com/itm/336747884909",
  "previousPrice": 54.90,
  "currentPrice": 49.90,
  "priceChange": -5,
  "currency": "USD",
  "listedAt": "2026-08-17T16:27:00",
  "firstSeenAt": "2026-08-10T09:00:00.000Z",
  "lastSeenAt": "2026-08-18T12:00:00.000Z",
  "detectedAt": "2026-08-18T12:00:00.000Z"
}

The type field tells the two apart: inventory_item for a current listing, and new_listing, price_change or removed for a change event.

Input reference

Setting	Type	Default	What it does
Sellers to monitor	list of text	—	The sellers to watch. Use eBay usernames, or links to their profile or store pages — mixed in the same list is fine. Keep the same list between runs so changes can be compared. Entries that are not eBay sellers are reported and skipped. Required.
eBay site	choice	US	Which country's eBay site to read. Prices come back in that site's own currency, and each site keeps its own change history per seller.
Maximum items per seller	whole number	1000	How many of each seller's newest live items to cover. To detect removed items reliably, set this above the seller's full inventory size. Maximum 5000.
Output the full current inventory	true/false	true	Output every currently listed item as its own row on every run, alongside any change events. Turn off to get change events only.
Parallel sellers	whole number	4	How many sellers to work on at the same time. Leave at 4 unless you have a reason. Maximum 10.

Output fields

Current-inventory rows (type = inventory_item)

Field	Type	Description
type	text	inventory_item for a current live listing.
seller	text	The seller this row belongs to, as you entered it.
marketplace	text	The eBay site the row was collected from.
itemId	text	eBay's item number.
title	text	Listing title as shown to shoppers.
condition	text	Item condition, when eBay states one.
subtitle	text	The seller's subtitle line, when present.
price	number	Listed price. For a price range this is the low end.
priceTo	number	The high end of a listed price range, when the listing shows one.
currency	text	Currency of the price, read from the eBay site itself.
originalPrice	number	The struck-through was-price, when the listing shows a markdown.
buyingFormat	text	BUY_IT_NOW or AUCTION.
bestOffer	true/false	Whether the listing accepts offers.
bids	number	Bid count on auction listings.
timeLeft	text	Time remaining, when eBay shows a countdown.
shippingCost	number	Delivery cost, or 0 when free.
freeShipping	true/false	Whether delivery is free.
freeReturns	true/false	Whether the listing offers free returns.
location	text	Where the item is located.
newListing	true/false	Whether eBay flags the item as newly listed.
listedAt	text	When the item was listed, in eBay's own display-local clock.
listedAtText	text	The listing time exactly as eBay rendered it.
imageUrl	text	Main image.
url	text	Clean listing link.
firstSeenAt	text	When this actor first saw the item for this seller.
capturedAt	text	When this row was collected.

Change events (type = new_listing, price_change or removed)

Field	Type	Description
type	text	new_listing, price_change, or removed.
seller	text	The seller this change belongs to.
marketplace	text	The eBay site the change was seen on.
itemId	text	eBay's item number.
title	text	Listing title.
url	text	Clean listing link.
previousPrice	number	The price on the previous run. Empty for a brand-new listing.
currentPrice	number	The price now. Empty for a removed item.
priceChange	number	Current minus previous, for a repricing.
currency	text	Currency of the prices.
listedAt	text	When the item was listed.
firstSeenAt	text	When this actor first saw the item.
lastSeenAt	text	The last run this item was still live.
detectedAt	text	When this change was detected.

Pricing

You pay per result, with no monthly minimum. There are two kinds of result.

What you are charged for	Price
Inventory item — one current live listing added to your dataset	$0.60 per 1,000
Inventory change detected — one new listing, price move or removal	$3.00 per 1,000

Change events are priced above plain inventory rows because they are the answer this actor exists to give you: what actually moved, worked out for you, instead of two full inventories to compare by hand. The first run for each seller records a starting point and produces no change events — so you are never charged for "changes" against a shop you have never looked at before.

Worked example. You watch 20 sellers with about 300 live items each, on a daily schedule. Each run outputs roughly 6,000 inventory rows (6,000 × $0.0006 = $3.60). On a typical day a handful of items move per seller — say 200 changes across all 20 (200 × $0.003 = $0.60). That is about $4.20 a day. If you only care about what changed, turn off the full-inventory output and pay for the change events alone.

Limits & what this actor cannot do

• The first run for a seller is a starting point, not a report of changes. It records what the seller has live right now so later runs have something to compare against. Change events begin on the second run.
• To be sure an item is really gone rather than just missing from one run, the actor waits until it stays absent across consecutive complete runs before reporting it removed — so a takedown may show up a run later than it happened.
• Removals are only judged when a run covers the seller's whole live inventory. If a run stops at the maximum-items limit, that run reports new items and price moves but does not decide anything was removed. Set the maximum above the seller's inventory size to catch removals reliably.
• It reports a seller's public live listings only — items currently for sale. Ended, sold and hidden listings are outside what this actor reads.
• Prices, bids and stock are a snapshot at the moment of collection and keep changing afterwards.
• Prices come back in the selected eBay site's own currency. Watching the same seller on two different sites keeps two separate histories, and a move between them is never mistaken for a price change.
• A seller with nothing currently listed and a username that does not exist look the same — both come back with no live items — so an empty result is not proof a seller is real but idle.
• On listings that take offers, and on auctions, the price shown is the listed price, not a hidden accepted or winning amount.
• Speed depends on the size of the job and on eBay's own response times; no fixed throughput is promised.
• eBay's terms govern automated access. You are responsible for using the data lawfully and in line with the source site's terms, and for handling any personal data in line with applicable privacy law.

FAQ

Do I need an eBay account? No. The actor reads only what eBay shows the public.

Does it need my login or password? No. There is nothing to connect and nothing to configure — paste the sellers you want to watch and press start.

Can I schedule it? Yes, and that is the point. Schedule it hourly, daily or weekly from the Apify console. Each run remembers the last one, so from the second run onward you get a clean list of exactly what changed.

Why did my first run show no changes? Because there was nothing to compare it to yet. The first run for each seller records a starting point; changes are reported from the next run onward.

How do I make sure removed items are caught? Set the maximum items per seller above the seller's full inventory size, so every run sees the whole shop. Removals are only decided when a run covers the entire live inventory.

Is the data complete? It covers everything a seller has listed publicly and live. Sold, ended and hidden listings are not part of what this actor reports, and it says so rather than guessing.