The question on your mind is probably here

SellerLibrary lets eBay sellers do product research, listing preparation and store tracking in one place. It reads stores' sales data, matches products with their Amazon counterparts to work out cost and profit, gets listings ready to publish on eBay, and watches the sources of live listings.

Sellers who sell, or are getting ready to sell, on the US marketplace (ebay.com). amazon.com is supported as a source, and prices are in USD.

Sign-up is by invitation for now. Fill in the early access form; applications are reviewed one by one and your invite arrives by email. Once your account is open, you connect your eBay store and install the Chrome extension.

Store scans, the Amazon search, ASIN collection and the address help on order pages run through the extension, and only in jobs you start. What it reads, what it doesn't and why it needs each permission are on the Chrome extension page.

For work done with the extension (store scans, the Amazon search, extension tracking), the computer and Chrome must be open. Products in the Seller Library Tracking System are checked on the server even with your computer off.

No. You connect your store on eBay's own permission screen; SellerLibrary never sees or stores your password. You can withdraw the permission in SellerLibrary's settings or in your eBay account.

Yes, as many as your package allows. Each store's policies, location and alerts are kept apart; the monthly new-listing allowance is shared by all your stores.

The Seller Library Tracking System checks products about every 12 hours, even with your computer off. With extension tracking you can choose 1, 2 or 4 checks a day; that needs the computer and Chrome open.

It means the value couldn't be read reliably in that check, for example because Amazon didn't show the page or asked for a verification. SellerLibrary doesn't guess; the time and value of the last real check are shown separately.

How many products the Tracking System watches at once is your package's tracking capacity; each package's capacity is on the Pricing page.

It's how many new listings your package lets you publish in each usage month. It's per user, so all your stores use the same allowance. What's left shows before you publish, and a listing eBay refuses doesn't count.

No. The allowance is used only by new listings that go live; updating a live listing's price, stock or content doesn't count.

eBay's selling limit and daily limits are separate from your SellerLibrary package, and each store has its own. If one fills, the job waits and says why; nothing is forced through.

No. A listing goes live in your own eBay account only when you press publish and approve eBay's fee preview.

eBay doesn't allow buying an item from another retailer and having it shipped straight to your buyer. SellerLibrary uses Amazon as a reference for price and cost comparison. You're expected to ship from your own stock or an agreed supplier, and you're asked to confirm this before publishing.

By the monthly new-listing allowance, the Seller Library Tracking System's tracking capacity and how many eBay stores you can connect. Packages and their prices show on the Pricing page as published.

Payment isn't open yet. When sales open, the price, renewal and cancellation terms are shown clearly before you buy, and card details are taken on the payment provider's own page.

Your current early access rights are kept. Any move to a paid package is announced in advance, you're never moved to a paid package without your consent, and you're never charged automatically afterwards.

When payment opens, the cancellation and refund terms are shown before you buy and are written in the Refund and cancellation document in the Document centre. A payment's entitlement opens only with a verified notice from the payment provider.

No. On the supplier's page the extension writes the delivery address into the form and stops before the payment step; you always complete the purchase yourself.

eBay's delivery confirmation depends on carrier data and eBay's own matching. SellerLibrary shows carrier movement, the number recorded on eBay and eBay's delivery confirmation apart; having one doesn't mean having the others.

Your research, products and drafts belong to your account only; other users can't reach them. Connection keys are stored encrypted. You can download all your data as one file and delete your account whenever you like.

If you have an account, write to the team from Help › Messages. If you don't, use the form on the Contact page or write to support@sellerlibrary.com.

Right now ebay.com (US) and amazon.com, with prices in USD. A marketplace that isn't supported says so on screen.