Inventory rules in SPL let you control exactly how much Shopify stock reaches TikTok Shop, rather than mirroring it one to one. In the TikTok Shop Connector app, go to Settings, then Product Settings, and you can sync a percentage of your stock, set a threshold that marks items out of stock early, assign fixed inventory to untracked products, and choose which Shopify and TikTok locations sync. Together these protect you from overselling.
Real-time sync keeps your numbers accurate, but inventory rules decide what those numbers should be. They are how you hold back a safety buffer, reserve stock for your own store, or keep untracked products sellable, all without touching your Shopify inventory.
This guide covers all four rules, what each is for, and how to combine them so you never oversell across two platforms.
TikTok Shop Integration — SPL
Gives you rule-based control over how Shopify stock maps to TikTok Shop: sync a percentage, hold a safety threshold, set fixed levels for untracked items, and pick which warehouses feed which platform. All on top of real-time syncing.
Watch: Setting up inventory rules in SPL
Here is the whole setup on screen. The written steps below explain what each rule does and when to reach for it.
Where to find inventory rules
Open the TikTok Shop Connector app in Shopify, go to Settings, then click Product Settings. All four inventory rules live here.
The four inventory rules at a glance
| Rule | What it does | Use it to |
|---|---|---|
| Percentage sync | Syncs a set percentage of Shopify stock | Reserve stock for your own store |
| Threshold inventory | Marks items out of stock at a set level | Stop selling before you hit zero |
| Fixed inventory | Assigns a set number to untracked products | Keep untracked items sellable |
| Location mapping | Chooses which warehouses sync | Control the source and destination of stock |
Rule 1: Inventory percentage synchronization
This lets you choose what percentage of your available Shopify inventory is synced to TikTok Shop, rather than all of it.
This is the rule to use when TikTok Shop is one channel among several and you do not want it able to sell your entire stock. It gives every channel a share and lowers the risk of overselling a fast mover.
Rule 2: Threshold inventory
This sets a threshold level that marks a product as out of stock in TikTok Shop once its inventory reaches that number, rather than waiting for it to hit zero.
It is your safety buffer. Set a threshold of 5, for example, and TikTok Shop stops selling the item once stock drops to 5, leaving you a cushion to cover orders already in flight, in-store sales, or slight timing gaps between platforms. This is one of the most effective guards against selling something you cannot actually ship.
Rule 3: Fixed inventory for non-tracked products
Some products in Shopify do not have inventory tracking switched on. Without a stock number to sync, they can behave unpredictably on TikTok Shop. This rule assigns a fixed inventory value to those untracked products so they stay consistently available.
It is useful for made-to-order items, digital-style products, or anything you always have available and do not count. Assign a comfortably high fixed number and those products stay sellable on TikTok Shop without you managing a real stock figure for them.
Rule 4: Inventory locations
The last two settings decide where stock flows from and to. They matter most if you run more than one warehouse.
TikTok inventory location
Specify the TikTok Shop warehouse where inventory synced from Shopify should be added. This tells TikTok which location holds the stock you are sending across.
Shopify inventory location
If you have multiple Shopify warehouses, select which inventory location should be synced with TikTok Shop. This is what lets you dedicate one warehouse to your TikTok channel, or point it at your main location, rather than pooling everything.
Want stock control, not just stock syncing? SPL lets you sync a percentage, hold a safety threshold, fix levels for untracked items, and choose your locations, so TikTok Shop never oversells. Free to install, plans from $9.99/month.
Install SPL free →How the rules work together
These rules are not either-or. A common, safe setup layers them:
- Percentage sync to give TikTok Shop a share of stock rather than all of it.
- Threshold inventory as a buffer so it stops selling before you truly run out.
- Fixed inventory so untracked products stay available and predictable.
- Location mapping so the right warehouse feeds the channel.
Set once, they run quietly in the background on top of real-time sync, which is what turns TikTok Shop from a channel you watch nervously into one you can leave to itself.
Inventory rule tips
✓ Set a threshold buffer on fast movers to absorb timing gaps between platforms
✓ Give untracked products a fixed value so they never drop out unexpectedly
✓ Map the correct Shopify location, since inventory syncs against a location
✓ Revisit your percentage during big sales, when a fast seller can clear stock quickly
✓ Layer the rules rather than relying on any single one
Inventory rules FAQs
How do I stop TikTok Shop from overselling my stock?
Use inventory rules in Product Settings. The two that matter most here are percentage sync, so TikTok Shop only ever sees a share of your stock, and threshold inventory, which marks an item out of stock before it truly reaches zero. Together they leave a buffer that absorbs orders already in progress and small timing gaps between platforms, which is where overselling usually creeps in.
What does inventory percentage synchronization actually do?
It syncs only a chosen percentage of your Shopify stock to TikTok Shop. If a product has 500 units and you set 50 percent, TikTok Shop shows 250. The rest stays reserved for your other channels. It is the simplest way to stop one platform from being able to sell everything you have.
What is threshold inventory for?
It marks a product as out of stock on TikTok Shop once its inventory falls to a level you set, instead of at zero. Setting a threshold of 5 means TikTok stops selling the item at 5 units, giving you a safety cushion for in-flight orders or sales on other channels. It is one of the most effective ways to avoid shipping problems.
What happens to products that are not inventory-tracked in Shopify?
Without a stock number to sync, untracked products can behave unpredictably on TikTok Shop. The Fixed Inventory for Non-Tracked Product rule assigns them a set value so they stay consistently available. Give them a comfortably high number if they are made-to-order or always in stock.
I have several Shopify warehouses. Which one syncs to TikTok?
Whichever you choose. Under the Shopify Inventory Location setting, select the warehouse that should sync with TikTok Shop, and use the TikTok Inventory Location setting to specify which TikTok warehouse receives it. This lets you dedicate a specific location to your TikTok channel rather than pooling all your stock.
Do inventory rules change my Shopify stock levels?
No. The rules only affect what quantity is presented to TikTok Shop when stock syncs. Your Shopify inventory stays exactly as it is, which means you can adjust a percentage or threshold freely without any effect on your core stock records.
Can I use more than one rule at once?
Yes, and most sellers should. A typical setup combines a percentage sync, a threshold buffer, fixed values for untracked items, and correct location mapping. Layering them gives you far tighter control than any single rule, and they all run together on top of real-time sync.
Keep going
More TikTok Shop guides.
The settings that surround inventory and keep selling smooth.
