Back in stock notifications: how to win back a customer when a product returns

A back in stock notification is a form on the page of an unavailable product that collects an email address and automatically sends a message when the product is back in stock. Simple. And the „out of stock” message stops being a dead end. Because what does a customer usually do when they land on a sold-out product? They close the tab and look for it at a competitor. A WooCommerce or PrestaShop store can instead give them an easy way to wait. Below I explain how it works, how to word the consent, what to write in the email, when to send it and how to set the whole thing up.

How does a back in stock notification work in an online store?

The customer leaves their email on the page of a sold-out product. The store adds it to a list, and when the stock level goes above zero again, it sends them a message. In the industry this is called back in stock, which means exactly what it says. The whole mechanism has three building blocks:

• a form shown only on unavailable products,
• a list of subscribers assigned to a specific product,
• an automatic email sent when the stock changes.

Without automation it makes no sense. Sure, you can track a waiting list by hand for a few items. But with hundreds of products and variants, someone will eventually forget to email a customer (not out of malice, just the daily grind), and that customer will buy somewhere else.

When does a „notify me when available” form make the most sense?

For products that come back in stock regularly. Not for items discontinued for good. Typical cases:

• seasonal products that run out before the sales peak,
• short runs and limited batches,
• popular sizes, colours and variants that sell out first,
• products with regular deliveries from the manufacturer.

When a product has been dropped from the range or there is no next delivery planned, it is better to hide the form. A sign-up that never leads to any message? It only frustrates people. And there is a second benefit few people think about: a waiting list shows real demand. When you place an order with your supplier, it is easier to judge how many units are worth buying in total.

Consent to the message: what the form must include

The form has to say clearly why the email address is being collected. Under the GDPR, processing personal data requires a legal basis and giving the data subject the relevant information, so agree the details with the person responsible for data protection in your company. In practice the rule is simple. Signing up for a back in stock notification is something different from consenting to a marketing newsletter. Want to collect marketing consent at the same time? Fine, but with a separate, unticked checkbox. Next to the email field and the button, a short, clear line such as „We will email you once when the product is back on sale” is enough. Instead of fine print nobody reads anyway.

A back in stock email that leads to a purchase

Short, to the point and one click away from the product page. That’s it. A good message has five elements:

1. a subject line with the product name, so the customer knows right away what it is about,
2. a product photo,
3. a clear statement that the product is available again,
4. a prominent button leading to the product page,
5. a reminder of why the recipient is getting this message.

It is tempting to add blocks with other offers or some „buy now before it’s gone!” nudges. In my opinion, don’t. They dilute the only goal of this email, which is getting back to one specific product. Keep the tone in line with the rest of your store’s communication, otherwise the email looks like spam from a stranger.

Timing: when to send the notification so the customer can still buy?

Right after the stock level changes. Not an hour later. With a small delivery there are sometimes more people signed up than units on the shelf, so every hour of delay lowers the chance the customer gets one. There is one catch: the stock in the store must be up to date. If the warehouse and the admin panel drift apart, the email leads to an empty shelf, and that puts people off more than no message at all. Oh, and one notification per restock is enough. No series of reminders the customer never asked for.

Klaviyo and WooCommerce: how to set up notifications without manual work

In a WooCommerce store you can connect notifications to Klaviyo, a platform that manages the subscriber list and sends the emails. This connection comes from the Klaviyo plugin for Woo by K4.pl. Once configured, it automatically adds a notification form to the page of an out-of-stock product. A customer who fills it in is added to the subscriber list in Klaviyo, and when the product returns, they get an automatic email about its availability. You can change the form texts in the settings, so it is easy to put a clear note about the purpose of the sign-up there.

Back in stock notifications as a permanent part of your store

Four steps. A form on the unavailable product, a clear note about the purpose of the sign-up, a simple email with a button to the product page and sending it right after the product returns. Set it up once and it runs on its own, nobody has to watch the lists. And a well configured back in stock notification turns an out-of-stock page into a chance for the customer to come back, instead of handing them to the competition.

Frequently asked questions