Back-in-stock alerts on Shopify: how to set up a "Notify me" button

A sold-out product page is a dead end. The shopper wanted the product enough to open it, and the page tells them to go away. A "Notify me when available" button turns that dead end into a list of people waiting to buy.

How a back-in-stock alert works

1. A shopper opens a product whose selected variant is sold out.
2. Instead of only a greyed-out button, they see Notify me when available.
3. They leave an email address. A logged-in customer just taps.
4. When stock returns, they get one email with a link straight to the product.

The important word is variant. If size M is sold out and size L is not, the button should appear only while M is selected, and the email should go out when M returns, not when any size does. Alerts that work at product level send people back to a page where their size is still unavailable.

Setting it up with ZS Wishlist

The Notify me button is part of ZS Wishlist & Notify Me from the Starter plan ($4.99/month, 14-day free trial).

1. Add the Wishlist Button block to your product template. The Notify me button lives inside it.
2. In the app, open Reminders and switch on Email reminders with Back in stock enabled.
3. Open Settings, switch on "Notify me" on sold-out products and save.
4. Open a sold-out product on your store to see the button.

Stock is checked once a day. When a product a shopper asked about is available again, the email is sent, and it is sent once per restock.

Four mistakes that make restock emails fail

1. Product-level instead of variant-level alerts

Covered above. It is the most common reason shoppers stop trusting the emails.

2. Asking for an account first

Someone looking at a sold-out product is already half-way out the door. A sign-up form finishes the job. Ask for an email address and nothing else.

3. No unsubscribe link

A restock alert is a marketing email in most countries. Every one needs a working unsubscribe link, and anyone who uses it must never be emailed again.

4. Sending the alert, then doing nothing else

People who asked for an alert are your warmest audience. If you use Klaviyo, send the request there as an event and build a flow from it. If you use Shopify's own tools, tag those customers and build a segment.

What it tells you about demand

Every request is a signal. Ten people waiting for one sold-out colour is a reorder decision made for you. Check which products collect the most requests before your next purchase order.

Next: how to add the wishlist itself, or the Notify Me section of the documentation.