WooCommerce does not email your customers when a product is back in stock: its stock emails go to you, the shop manager. Since WooCommerce 11.2 there is a “Back in stock notifications” option under WooCommerce > Settings > Advanced > Features, but WooCommerce itself still calls it experimental, so most shops use a waitlist plugin that adds a “Notify me” form to sold-out products and sends the emails when the stock comes back. If the form shows on simple products but not on variable ones, the usual cause is that the sold-out variation can’t be selected, so the form has nothing to attach to.

Why it happens

  • WooCommerce’s own stock emails are for you, not for the customer. The “Enable low stock notifications” and “Enable out of stock notifications” options in WooCommerce > Settings > Products > Inventory send an email to the notification recipient you set there. Customers never receive them.
  • “Hide out of stock items from the catalog” is on. With this option on, WooCommerce also leaves sold-out variations out of the size and colour menus. The customer can’t pick them, so no waitlist form appears. The official Back In Stock Notifications extension tells you to turn this option off for the same reason.
  • The theme or a swatches plugin disables sold-out options. Many themes and swatch plugins grey out or remove out-of-stock variations. That looks tidy, but it hides the form too. In a YITH Waitlist support thread about this exact symptom, support asked the user to find “which setting is disabling the out-of-stock variation selection”.
  • The product is not really out of stock. If “Allow backorders” is on, the product shows as “Available on backorder”, it can still be bought, and waitlist plugins usually don’t show the form.
  • The block product page. An open WooCommerce issue (#70182, October 2026) says the core experimental feature doesn’t follow the selected variation in the Add to Cart + Options block yet. Simple products work.
  • The stock came back, but nothing was sent. Emails go out from the background queue (Action Scheduler). If WP-Cron doesn’t run on your server, or your shop mail doesn’t arrive, signups pile up unsent. Stock changed directly in the database by a sync or import tool may not trigger the alert at all.

How to check

  1. Open a sold-out simple product in a private browser window. If the “Notify me” form shows there, the plugin works and the problem is limited to variations.
  2. Go to WooCommerce > Settings > Products > Inventory and look at Out of stock visibility. If “Hide out of stock items from the catalog” is ticked, that explains the missing variations.
  3. Open the variable product and choose the sold-out size or colour. If you can’t choose it (it’s missing or greyed out), check your theme options and any swatches plugin for a setting such as “disable out of stock variations”.
  4. In the product editor, open Variations and expand the sold-out one. Its stock status must be “Out of stock”, or its stock quantity must be 0 with stock management on. Check that “Allow backorders” is set to “Do not allow”.
  5. Switch to the Storefront theme for a few minutes (on a staging copy if you can) and check again. If the form shows, the theme is the cause.
  6. To test sending, sign up with your own email, set the stock back above 0 and wait a few minutes. Then look in WooCommerce > Status > Scheduled Actions for pending or failed actions from your waitlist plugin.

How to fix it

If you don’t have a waitlist yet:

  1. Make a backup.
  2. Install a waitlist plugin that supports variations. There are several free ones on WordPress.org; for example, “Back In Stock Notifier for WooCommerce” lists simple and variable products in its free features. The official extension, Back In Stock Notifications, is paid.
  3. If you’re on WooCommerce 11.2 or newer and want to try the built-in option, turn on WooCommerce > Settings > Advanced > Features > Back in stock notifications, but test it on a staging copy first: it’s still experimental.

If the form doesn’t show on variations:

  1. Untick Hide out of stock items from the catalog in WooCommerce > Settings > Products > Inventory. If you want sold-out products to stay out of the shop pages, keep them findable some other way; a hidden variation can’t collect signups.
  2. In your theme or swatches plugin, choose “show as out of stock” (crossed out or greyed but clickable) instead of “hide” or “disable” for sold-out variations.
  3. Set backorders to “Do not allow” on the products where you want a waitlist instead.
  4. Clear your page cache and test again in a private window.

If people signed up but got nothing:

  1. Check WooCommerce > Status > Scheduled Actions. A long list of past-due actions means WP-Cron isn’t running; ask your host to set up a real server cron job.
  2. Send yourself a test order email. If it doesn’t arrive, fix your shop mail first (an SMTP plugin and the SPF and DKIM records for your domain).
  3. If your stock comes from an ERP, a marketplace or a CSV import, update one product by hand in WooCommerce and see whether the alert goes out. If it does, the sync is writing stock without going through WooCommerce; ask its developer how to trigger the stock status change.

How to keep it from happening again

The cause that keeps coming back is the variable product: the form has to appear as soon as the customer picks a sold-out size or colour, and the emails have to go out without you thinking about it. That is what our plugin RestockCraft does. It adds the “Notify me” form to every sold-out simple product and to each variation, and it works with page caching. When the stock comes back it emails people in signup order through the WooCommerce background queue, and with its fair queue it only tells as many people as there are units (for example, 3 units, the first 6 people), then moves on to the next people if units are still unsold after the hours you choose. Each email can carry a single-use personal coupon, and the dashboard shows the money waiting on your lists and the sales that came from the alerts. It costs 29 USD a year for one site or 59 USD lifetime, and you can try it in the demo. If a free plugin covers what you need, use that.

Frequently asked questions

Does WooCommerce have back-in-stock notifications built in? Since version 11.2 there is an option under WooCommerce > Settings > Advanced > Features, but WooCommerce marks it as experimental. Until it’s stable, most shops use a plugin.

Why does the waitlist work on simple products but not on variable products? Usually because the sold-out variation can’t be selected: “Hide out of stock items from the catalog” is on, or the theme or a swatches plugin disables sold-out options. No selected variation, no form.

Do I have to show out-of-stock products to collect signups? Yes. A customer can only sign up on a product or variation they can see and select.

Why didn’t the customer get the email when I restocked? Check, in this order: that the product actually changed to “In stock”, that Scheduled Actions are running, and that your shop mail arrives. Stock written directly by an import or sync tool may not trigger the alert.

Is my “out of stock” email from WooCommerce the same thing? No. That email goes to the shop manager. After WooCommerce 10.8 it stopped arriving for many shops, and WooCommerce said the fix would come in 10.9; it never tells customers anything.