A customer lands on your best-selling product page, adds it to cart, and gets to checkout only to find out it’s out of stock. Or worse, they don’t find out until after they’ve paid, and now you’re issuing a refund and an apology email. Either way, you’ve lost the sale, and possibly the customer’s trust in your store.
For Australian merchants relying on overseas manufacturing or suppliers with long lead times, this isn’t a rare edge case, it’s a recurring operational problem. Container shipping delays, supplier minimum order quantities, and unpredictable freight timelines mean stock gaps are almost inevitable at some point. The question isn’t how to avoid them completely; it’s how to handle them so you don’t lose the sale, and don’t lose the customer’s trust either.
This post covers how Shopify’s native inventory settings handle out-of-stock scenarios, where they fall short, what backorder and waitlist apps add on top, and how to think about when continuing to sell out-of-stock is the right call versus when it damages more than it helps.
What Shopify’s Native “Continue Selling When Out of Stock” Setting Actually Does
Shopify has a built-in setting on every product variant that controls this. In your Shopify admin, go to Products, open a product, scroll to the Inventory section, and you’ll see a checkbox: “Continue selling when out of stock.”
When this is switched on for a variant:
- Customers can still add the item to cart and complete checkout even when tracked inventory hits zero (or goes negative).
- The product page will typically still show as available for purchase rather than displaying “Sold out.”
- Inventory counts can go negative in your admin, which is normal and expected behaviour when this setting is active, it’s not an error.
When it’s switched off (the default), Shopify blocks the add-to-cart action once inventory reaches zero, and the storefront shows a “Sold out” state instead of a buy button.
What this setting does not do
This is the important part, because it’s where a lot of merchants get caught out. The native setting is a binary switch, it doesn’t give you:
- Any way to communicate an expected restock or ship date to the customer at the point of purchase
- A separate “backorder” order status distinct from a normal in-stock order, as far as Shopify’s order management is concerned, it’s just an order
- Automatic customer notifications about delays
- A waitlist or “notify me” capture for customers who don’t want to buy blind
- Any built-in messaging differentiating “ships today” from “ships in 6 weeks” on the product page
In other words, native Shopify lets you keep selling past zero stock, but it doesn’t manage the backorder experience. If you switch this on and do nothing else, customers are placing orders with no idea their item might not ship for weeks. That’s where trust erodes, not from the backorder itself, but from the silence around it.
Backorder and Waitlist Apps Worth Knowing About
For AU merchants dealing with genuine backorder scenarios, not just occasional restocking gaps, but planned pre-sell or long supplier lead times, a dedicated app usually does more of the work than native settings alone. Broadly, there are two categories:
“Notify me when back in stock” waitlist apps. These add a capture form on out-of-stock product pages so customers can leave their email (or sometimes SMS) and get notified automatically when stock is replenished. This suits situations where you’d rather not sell blind, you keep the product looking properly “sold out” but capture demand instead of losing the visitor entirely. It’s a lower-commitment option than a full backorder and works well for genuinely unpredictable restock timing.
Backorder and ETA messaging apps. These sit on top of the “continue selling” behaviour and add explicit backorder messaging at the product page and cart level, things like a badge saying “Ships in 3-4 weeks” or “Backordered, expected [date],” and sometimes logic to prevent mixed carts (in-stock and backordered items shipping separately) causing fulfilment confusion. Some also handle automated post-purchase email sequences specifically for backordered items, which matters a lot for setting expectations after the sale, not just before it.
Which one fits depends on your situation. If your stock gaps are short and unpredictable, a waitlist app is usually the safer default, it doesn’t ask customers to commit to an unknown wait. If you’re deliberately running a pre-sell or you know backorder timing with reasonable confidence (say, a fixed shipping schedule from an overseas supplier), an explicit backorder-with-ETA approach can actually work in your favour, because it converts sales you’d otherwise lose to a competitor while stock is in transit.
When Continuing to Sell Out-of-Stock Makes Sense, and When It Doesn’t
This is a judgement call, and it depends heavily on your supply chain and product category.
It tends to work well when:
– You have a reasonably reliable restock date (e.g. a confirmed shipment already in transit)
– The product is a considered purchase where customers are used to waiting (furniture, made-to-order goods, certain fashion pre-sells)
– You communicate the timeline clearly and set expectations before payment, not after
It tends to backfire when:
– Lead times are genuinely uncertain (a supplier hasn’t confirmed a ship date, or freight delays are common on that route)
– The product is an impulse or low-consideration purchase where customers expect near-immediate shipping
– You go quiet after the order is placed, no confirmation of the delay, no updated ETA, no proactive email if the date slips
For a lot of Australian merchants importing from overseas manufacturers, freight variability is the real risk here. A restock date that looked solid when the order shipped can slip by weeks if there’s a port delay or customs hold. If you’re going to promise a date on the product page, build in a buffer, and make sure your post-purchase flow can handle a slip gracefully rather than leaving the customer to find out only when their order is late.
Communicating Delays Honestly
The mechanics matter less than the communication. A few practical principles:
- Be specific, not vague. “Currently backordered, ships in approximately 3-4 weeks” is more trustworthy than “temporarily unavailable” or no messaging at all.
- Repeat the message at every touchpoint. Product page, cart, order confirmation email, and (if there’s any change) a proactive update email. Don’t rely on the customer remembering what the product page said three weeks ago.
- Set the expectation before the customer pays, not in the confirmation email after. Finding out about a six-week wait after checkout feels like a bait-and-switch even if it wasn’t intended that way.
- Have a plan for when the date slips. If your ETA moves, an automated or manual check-in email beats silence every time. Customers who ordered from you are far more forgiving of a delay they’re told about than one they discover by contacting support.
Inventory Buffers and Safety Stock Thinking
A backorder strategy is really a symptom-management tool, the underlying fix is better inventory planning. For AU merchants dealing with international freight variability, a few practical habits help reduce how often you’re relying on backorders in the first place:
- Build a safety stock buffer based on your worst realistic lead time, not your average one. If your supplier normally ships in 4 weeks but has occasionally taken 8, plan reorder points around something closer to the 8-week scenario for your bestsellers.
- Track sell-through rate against incoming shipment timing, not just current stock levels, so you can see a gap coming before you actually hit zero.
- Segment which SKUs can tolerate a backorder model and which can’t. Hero products with high purchase intent and low brand loyalty (customers will buy the competitor’s version if yours is out) are the ones where backorders hurt most. Niche or loyalty-driven products can often tolerate a longer wait without losing the sale to a competitor.
- Sync your inventory data properly if you’re running multiple sales channels or a 3PL, so the “continue selling” setting isn’t creating oversell risk against stock that’s already been promised elsewhere.
This is really an inventory management and integrations problem as much as a Shopify settings problem, getting accurate, real-time stock visibility across your supplier, warehouse, and storefront is what makes the backorder decision easier to get right in the first place. If your current setup involves manual stock updates or disconnected spreadsheets feeding into Shopify, that’s usually the root cause of both oversells and awkward backorder situations. Our Shopify inventory management integration work is generally where we start with merchants dealing with this, connecting Shopify to the systems that actually hold your real stock and lead-time data so the storefront reflects reality more consistently.
A Practical Framework for Handling Low Stock and Backorders
- Classify your SKUs. Which products can tolerate a backorder model, and which need to stay strictly “sold out” until back in stock?
- Decide your default behaviour per category, waitlist capture for unpredictable restocks, explicit backorder-with-ETA for predictable ones.
- Configure the native setting deliberately, not by accident. Check “Continue selling when out of stock” per variant against the decision you made in step 2, rather than leaving it as a blanket store-wide default.
- Add messaging at every touchpoint, product page, cart, confirmation email, for anything sold on backorder.
- Build a buffer into your quoted ETA based on your worst-case, not average-case, freight timeline.
- Set up proactive delay communication for when the ETA slips, rather than waiting for the customer to ask.
- Review inventory sync accuracy regularly if you’re running multiple channels, warehouses, or a 3PL, so backorder decisions are based on real numbers.
FAQ
Does Shopify have a built-in backorder feature?
Not a dedicated one. Shopify’s native “Continue selling when out of stock” setting (found on each product variant under Inventory) lets customers purchase past zero stock, but it doesn’t add restock date messaging, waitlists, or backorder-specific order handling. Apps fill that gap.
Should I let customers buy products that are out of stock?
It depends on how reliable your restock timeline is and how considered the purchase is. It tends to work well for products with predictable restock dates and customers used to waiting; it tends to hurt trust for impulse purchases with vague or unreliable timelines, especially if the delay isn’t communicated clearly before checkout.
What’s the difference between a waitlist app and a backorder app?
A waitlist (“notify me when back in stock”) captures customer interest without taking payment, the product stays marked as sold out and the customer is emailed once it’s restocked. A backorder app lets the sale go through immediately but adds explicit messaging about expected ship dates, usually at both the product and cart level.
How do I stop overselling products that are genuinely out of stock everywhere, not just backordered?
This usually comes down to inventory sync accuracy across whatever systems hold your real stock numbers, your 3PL, supplier, or other sales channels. If Shopify isn’t getting accurate, close-to-real-time updates from those sources, the “continue selling” setting can create oversells you didn’t intend. Proper inventory integration work is the fix here.
How far in advance should I build a buffer into my quoted restock dates?
There’s no fixed number that applies to every business, but a reasonable practice is to base your quoted ETA on your worst realistic lead time rather than your average one, particularly if you’re importing via international freight where delays are common. Padding the date slightly and beating it looks better to customers than promising an optimistic date and missing it.
Next Step
If backorders and stock gaps are a regular headache rather than an occasional annoyance, it’s usually worth looking at the inventory system feeding your Shopify store, not just the storefront messaging. Book a strategy call or start with a Shopify audit and we’ll help you work out whether the fix is a better app setup, better supplier lead-time planning, or a proper inventory integration.
