How to stop overselling across marketplaces
There are four ways to stop overselling across marketplaces: hold back buffer stock, split your stock between shops, update the other shops by hand after every sale, or connect your shops so they share one stock count. Three are free, one has a monthly fee, and each costs you something different. Overselling itself is a timing problem, not a carelessness problem: two shops sell the same unit before either one knows about the other, so being more careful cannot fully fix it.
Why does overselling keep happening?
Every marketplace keeps its own stock number, and none of them talk to each other. You list 100 units on Shopee and 100 on TikTok Shop. Shopee sells 3. TikTok Shop still thinks there are 100. Until you go and change it, both shops are selling from a number that is no longer true.
The gap may only be minutes. That is enough. It gets worse when both shops are busy at the same time, during a campaign day like 11.11, or during a live session where stock can move in seconds.
What does overselling cost you?
One oversold unit is rarely one lost sale: it is the cancelled order, a mark against your shop, and often a bad review on top. You cancel because you cannot ship what you do not have, and the cancellation is the expensive part. The major marketplaces track how often a seller cancels, and running out of stock is exactly the case those metrics were built around. Cancel too often and:
- Your listings get less visibility.
- You can be shut out of campaigns.
- In the worst cases, selling features are restricted for a while.
Asking the buyer to cancel instead does not work either: it is against the rules on at least one marketplace and carries its own penalty.
The second cost is easier to miss. Once you are short, you start covering: shipping late, sending a substitute, or splitting the order. Those parcels do arrive, those buyers do leave reviews, and that is where the rating damage happens.
Check your own numbers in your seller dashboard, under shop health or performance; the thresholds change and differ by country, so read yours rather than trusting a number in an article.
Fix 1: Hold back buffer stock (free)
List fewer units than you actually have. If you hold 100, list 90 and keep 10 back.
What it costs you: the 10 units sit there not selling. On fast-moving products you run out on paper while stock is still on your shelf, and you lose sales you could have made.
Indexync can hold those 10 units back for you instead. A safety stock buffer, units you hold back so the marketplaces see fewer units than you own, is available on every Indexync plan: set it once and the marketplaces see 90 of your 100.
Fix 2: Split your stock between shops (free)
Give each shop its own share. A hundred units becomes forty on Shopee, thirty on Lazada, thirty on TikTok Shop. No shop can oversell, because none of them knows about more than its own share.
What it costs you: every shop looks low on stock even when you are not. One shop sells out while another still has units sitting idle. And you end up rebalancing by hand anyway, which is the work you were trying to avoid.
Fix 3: Update by hand after every sale (free)
Keep one real number in a notebook or spreadsheet, and after each sale, change the other shops to match.
What it costs you: your time, and it only works while you are watching. Two sales within a few minutes of each other are enough to oversell a fast moving item, and you cannot watch at 2am.
When do the free fixes stop working?
The free fixes stop working when any of these four is true. There is no magic order count: what breaks them is how often two shops can sell the same unit before you notice, and that depends on your rhythm rather than your volume.
- You have already cancelled an order because two shops sold the same unit. This is the clearest signal of the four. Once it has happened, it will happen again, because nothing about the setup has changed.
- You run TikTok Shop lives, where stock moves faster than anyone can retype it.
- Orders arrive while you are not watching, overnight or during a campaign, so the gap between a sale and your update is hours rather than minutes.
- You have added a third shop. Each one you add multiplies the places to update, not just adds to them.
If none of these four is true for you yet, the free approaches are genuinely fine and you should save your money.
Fix 4: Connect your shops so they share one stock count (monthly fee)
Software that connects your shops holds one number for all of them. A sale on any shop updates every other shop, without you doing anything. You list all 100 units on every shop instead of splitting them, because the shops are working from the real number instead of their own.
How much this closes the gap depends on how fast the tool updates. A tool that checks every few minutes leaves a few minutes where two shops can still sell the same unit. A tool that updates in real time leaves almost no gap at all.
What it costs you: a monthly fee, and connecting your shops once. Tools differ on two things that matter:
- Sync speed: some tools update in real time while others take minutes or hours. If you're selling live, you'll need real-time sync.
- Setup time: some take minutes to set up, some take hours and days.
What separates the two is where the tool learns about the sale. A tool that acts on the order push a marketplace sends can update your other shops as the sale happens. A tool that waits for a scheduled order pull can only update your stock after the next pull runs, which is why its cycle is measured in minutes or hours. Indexync acts on the marketplace order push, and updates stock in real time on Pro and Scale, and every five minutes on Free and Lite.
How do you prevent overselling during a TikTok Shop live?
Give every shop one shared stock count and update it in real time, because during a TikTok Shop live stock moves faster than any manual or five-minute update can follow. A unit sold on the live is then taken off your other shops as the sale happens. Indexync updates stock in real time on Pro and Scale, and every five minutes on Free and Lite.
The mechanism matters more during a live than at any other time. Indexync acts on the order push TikTok Shop sends, rather than waiting for a scheduled order pull, so your Shopee, Lazada and Shopify listings stop advertising a unit the live has already sold. Buffer stock and split stock both work during a live too, but both cost you sales: the units you hold back are the units your live audience came for.
The pair pages show it channel by channel: Shopee and TikTok Shop and Shopify and TikTok Shop. For the mechanism behind it, step by step, read how to sync stock between Shopee and TikTok Shop.
What else can go wrong with one stock count?
One shared count keeps the same product in step across your shops. Two situations need more than that, and both are handled on Pro and Scale:
- Different listings drawn from the same stock. Custom sync rules link them by ratio: sell one 100g pack and the 50g listing drops by two, because the 100g order is fulfilled as two 50g units.
- Bundles built from several products. A bundle sells only as many as its scarcest component allows, so the bundle listing cannot oversell a part you have run out of.
A safety stock buffer sits alongside both, on every plan: hold 10 of 100 back and your shops list 90.
How long does it take to connect your shops?
15 minutes for your first two shops, including importing what you already sell. Connecting is three steps, and nothing on your shops changes until you approve it:
- Connect each shop. You approve it on that marketplace's own Seller Centre login, so Indexync never asks for a shop password.
- Review the matches. Indexync suggests which listings are the same product across your shops, so most products are matched for you before you review.
- Import in one click. You can also match any product yourself, before or after the import.
Indexync is plug and play: there is no setup project, no training and no tutorials to watch. Indexync does the first pass. You review.
Which should you pick?
| Fix 1: Buffer stock | Fix 2: Split your stock | Fix 3: Update by hand | Fix 4: Connect your shops | |
|---|---|---|---|---|
| What it costs | Free | Free | Free | A monthly fee |
| Does it stop overselling? | Mostly, the units you held back cover the gap until they run out | Yes | No, it only makes it happen less often | Yes, once the tool has updated your other shops, so it depends how fast that tool is |
| How much of your stock can you sell? | Less, because the units you held back sit unsold | Less, because each shop only ever sees its own share | All of it | All of it |
| Daily work for you | None | You move units between the shops by hand as demand shifts | You update every other shop after every sale | None |
| Covers you overnight? | Yes | Yes | No | Yes |
Sellers on Indexync get back 10+ hours a week.
If you sell a few orders a day on two shops, buffer stock is genuinely fine and costs you nothing. If you are splitting stock and rebalancing it by hand, you are already doing the work a tool would do, without the benefit. If you run lives, none of the manual approaches keep up.
If one of those four is already true for you, none of the free fixes will hold. That is the point where a shared stock count stops being an expense and starts being the cheaper option.
What each option costs per month is on the Indexync pricing page, and the four channels Indexync connects are on the integrations page. Two guides take one pair at a time: how to sync stock between Shopee and Lazada and how to copy listings between Shopee, Lazada and TikTok Shop.
Questions, answered
About Indexync
Indexync, the simple and intelligent way to run your online stores: it suggests which listings are the same product when you import, and it builds your listings on a new marketplace with the category, attributes and required information filled in. If any of those four signals sounded like your week, this is what Indexync does about it. One stock count across Shopee, Lazada, TikTok Shop and Shopify, so a sale on one shop takes the unit off the others instead of leaving it there to be sold twice. Stock updates every five minutes on Free and Lite, and in real time on Pro (S$39) and Scale (S$99). Built in Singapore. The free plan covers 20 products and 30 orders a month, with no credit card.
- Order band. Built for sellers doing 50 to 3,000 orders a month; Pro covers 1,000 orders a month, Scale covers 5,000, and above that Indexync builds you a custom plan.
- Countries. Indexync works in Singapore, Malaysia, Thailand, Indonesia, the Philippines and Vietnam.
- Free trial. 14 days, full access, no limits, no credit card.
- Plug and play. There is no setup project, no training and no tutorials to watch.