Selling in more than one place is one of the best things a small business can do: your own website, a marketplace like Etsy, eBay or Amazon, and maybe a market stall or a shop counter. Each one brings customers the others don't.
It also means one candle, one print or one jar of honey is listed in several places at once. When it sells in one, the others have to find out. When they don't, you sell something you no longer have.
The signs
- A customer orders something that sold out days ago, and you only find out when you go to pack it.
- An item shows as in stock online, but the shelf is empty. Or the other way round.
- The same product has a different count in each place, and nobody can say which one is right.
- You've started doing a quick recount before every busy weekend, just in case.
None of this means anyone did a bad job. It's what happens when separate systems are expected to agree, and nothing checks that they still do.
Why counts drift apart
Usually something copies sales from one place to another: a sync app, a plugin, an automation, or a person with a spreadsheet. Counts drift when that copying misses something. These are the most common reasons:
- The sync stopped, and nothing said so. A login expired or the sync was switched off, and every place carried on selling from the last numbers it had. This guide on automations that stop quietly covers it in detail.
- Products are matched by name. If the sync pairs products by name, "Lavender & Cedar" on your website and "Lavender and Cedar" on Etsy are two different products to it. It skips them, quietly, every time.
- Two sales land close together. Some syncs copy one place's count over the other's. If the same item sells in both places before the next sync, one of those sales can go missing from the count.
- In-person sales are added later. Market or shop sales often go in by hand at the end of the day or the weekend. Until then, your online shops don't know about them.
- Options don't line up. A product with sizes or colors needs each option matched separately. One unmatched option, like a large in blue, can drift on its own while the rest look fine.
- Returns aren't counted back. A returned item goes back on the shelf, but only one place adds it back to the count, or none does.
A 15-minute weekly check
Pick a quiet moment once a week. You don't need to check everything, only the products most likely to go wrong.
- Pick your five best sellers. Fast-moving items drift first, and cost the most when they oversell.
- Write down their count in each place. Your website, each marketplace, and your own record or spreadsheet. A simple table is enough.
- Compare them with what's on the shelf. If every number agrees, great. If one place is different, note which one and by how much.
- Look for a pattern. Is it always the same product? The same marketplace? Always after a market weekend? A pattern points straight at the cause.
- Check the sync's last run. If you use a sync app or an automation, look at when it last ran, and whether it lists any errors or products it couldn't match.
Keep each week's table. After a month it tells a clear story, and it's exactly what anyone helping you will want to see.
Habits that stop overselling
- Give every product a stock code, the same one everywhere. Shops often call it a SKU. Many sync tools can match products by this code instead of by name, so renaming a product can't quietly break the link. Check whether yours can.
- Keep a small buffer on your best sellers. Show one or two fewer online than you really have. You'll rarely miss a sale, and you'll rarely oversell.
- Lower the online count before a market weekend, and put it back once your stall sales are in.
- Make one place the master. Decide which count is the true one, and have every other place follow it, rather than all of them copying each other.
- Ask for a warning when the sync stops. A short daily "it ran" message, or a missing one, tells you before a customer does.
When to ask for help
If the counts keep drifting and the weekly check doesn't show you why, the cause is usually inside the sync itself: in how products are matched, or in when the updates run. That part is hard to see from the outside.
That's what my starter review looks at, read-only. This example findings note is for a candle shop with exactly this problem: what was causing it, and what to change first.