Back in Stock Notifications on Shopify: Turn Sold-Out Products into Sales
Every sold-out product page is a shopper who wanted to buy and couldn’t. Most of them leave and don’t come back, and some buy the same thing from a competitor. A back-in-stock alert turns that dead end into a waiting list: the shopper leaves their email, and you tell them the moment the product returns.
These are some of the highest-intent emails a store can send. The person asked for it, about a product they already chose. Here’s how to get it right.
How back-in-stock alerts work
- A product or variant hits zero stock.
- The add-to-cart button is replaced by a “Notify me when available” button.
- The shopper enters their email and joins the waitlist for that exact variant.
- When inventory goes back above zero, everyone on the waitlist gets an email with a link to buy.
On Shopify, the reliable way to detect a restock is through inventory webhooks, so the alert goes out automatically when you receive stock, with no manual sending.
Best practices for the Notify Me button
- Work at variant level. If size M is sold out but L isn’t, only M should show the button. Someone waiting for M doesn’t want an email when L restocks.
- Put it exactly where add-to-cart was. Shoppers already look there. A tiny text link below the fold won’t get used.
- Match your theme. A button that looks like a third-party widget feels untrustworthy. Use the same font, colours and corner radius as your add-to-cart button.
- Keep the form to one field. Email only. Every extra field lowers sign-ups.
- Confirm instantly. Show a clear “You’re on the list, we’ll email you when it’s back” message so shoppers know it worked.
Writing a restock email that converts
The email has one job: get the shopper back to the product page before the stock runs out again.
- Subject line: name the product. “The Midnight Runner in size 42 is back” beats “Good news!” every time.
- Show the product image and the exact variant they asked for.
- One clear button that links straight to the product with the variant pre-selected.
- Honest urgency: if stock is limited, say so. Don’t invent scarcity.
- Speak your customer’s language. If you sell in French or Arabic, send the alert in French or Arabic, with right-to-left layout where needed.
Consent and privacy
A back-in-stock signup is consent to receive that notification, not your newsletter. If you also want to add people to your marketing list, ask separately with an unticked checkbox. For EU and UK shoppers, add a short consent line under the form. Double opt-in (a confirmation email before joining the waitlist) gives you the cleanest list.
Use your waitlist as demand data
Waitlists are more than an email list. They tell you exactly which products and variants people want and can’t buy:
- A long waitlist on one size is a signal to order deeper on that size next time.
- Waitlist size helps you decide what to reorder first when cash is tight.
- Products with no waitlist after selling out may not be worth restocking at all.
Common mistakes
- Notifying 500 people when only 20 units came back, which creates frustration. Restock deeper or set expectations in the email.
- Sending the alert from an unbranded address that lands in spam. Use your own domain with SPF and DKIM set up.
- Hiding sold-out products from collections. Keep them visible with the Notify Me button so you keep capturing demand.