How eBay Order Sync Actually Works
(And Why Some Tools Stop When You Close Your Laptop)

The question nobody asks before buying

Every eBay tool says it syncs your orders. Almost none of them say where the sync runs, and that single detail decides whether it works on a Sunday when your laptop is shut.

There are two architectures. They look identical on a feature list and behave completely differently in practice.

Browser-side versus server-side

	Browser extension	Server-side job
Runs when	Your browser is open	Always, on a schedule
Laptop closed	Stops	Keeps running
Sees your logged-in session	Yes	No
Needs eBay authorisation	Not necessarily	Yes — OAuth
Survives you changing computers	No, re-install	Yes

Neither is better in the abstract. They are good at different things, and a well-built tool uses both — for different jobs.

What only a browser can do

Reading a supplier's page as you see it. Amazon shows different prices and availability depending on region, Prime status and account history. A server making an anonymous request from a data centre sees a different page than the one your order will actually be placed against — when it is not served a CAPTCHA instead. For supply-price monitoring, the browser is not a workaround; it is the only way to get an accurate reading.

What only a server can do

Keep working. Orders arrive at three in the morning. Suppliers change stock on a Sunday. Anything that has to happen on a schedule regardless of what you are doing has to live somewhere that is always on.

If a tool's order sync is browser-based, it is not really automation. It is a macro that runs when you happen to be at your desk.

What "syncing an order" actually involves

It is more than pulling a row of data. A complete cycle does five things:

1. Fetch new orders — buyer, shipping address, item, quantity, price paid, currency
2. Match each order to a product you already track, so the profit calculation has a cost to work against
3. Track fulfilment state — paid, dispatched, delivered — and advance it as eBay does
4. Push tracking back — the number and carrier you shipped under, sent to eBay so the buyer sees it
5. Close the loop — turn a delivered order into a completed sale with a final profit figure

Step 2 is where tools quietly fail. An order that is not matched to a product has a sale price and no cost, so it contributes revenue and no profit — and your margin figures are wrong in a direction that flatters you. If a tool cannot tell you how many of your orders are unmatched, that number is not zero.

Why OAuth matters more than it sounds

Server-side sync needs eBay's permission, granted through OAuth: you log in at eBay, approve specific permissions, and eBay issues a token to the tool. Your password is never shared, the token is limited to what you approved, and you can revoke it from your eBay account at any time without changing your password.

The alternative — a tool that asks for your eBay password, or drives your logged-in browser session against eBay — is worse on every axis. It has no permission boundary, no revocation, and it is the pattern eBay's automation rules are designed to catch.

One practical consequence: the permissions matter individually. A tool that requested read access to orders but not write access to fulfilment can pull your orders and will silently fail to push tracking. Worth checking what a tool actually asked for.

How often is often enough?

More frequent is not automatically better. Every marketplace API has call limits, and burning them on a five-minute poll leaves nothing for listing or revising.

For arbitrage the useful interval is the one that beats your own reaction time. If you check orders twice a day, a 30-minute sync is already far ahead of you. The value is not being notified within seconds; it is that the state is correct whenever you look, without you having pressed anything.

How ArbiKey is built

ArbiKey uses both, deliberately, with each doing what only it can:

• Server-side, every 30 minutes: eBay order sync — new orders, buyer and shipping details, fulfilment status, item images. Runs on a schedule whether or not you are logged in.
• Server-side, on a schedule: supplier stock sync, setting listing quantity to zero and restoring it, never ending a listing.
• Server-side: tracking push to eBay and delivery status back.
• Browser extension: supply price and stock monitoring, and product import — the jobs that need your own session to be accurate.

The eBay connection is OAuth through eBay's official API, with a separate connection per store, revocable from your eBay account. And every synced order is matched to a product and priced against the real final value fee for its category, the international fee, ad rate, VAT and the day's ECB rate — so the profit you read is the profit, not revenue with an assumption applied.

ArbiKey also stops deliberately at one step: it never places the supplier order for you. Having a retailer ship directly to your eBay buyer is against eBay's dropshipping policy, and it is enforced. You source and ship; ArbiKey records the supplier order and cost and keeps the numbers honest.

Common questions