Back in stock feature

What is required to enable Back in stock?

An E-mail trigger plugin with Back in stock support

How does Back in stock feature work?


Customers can subscribe to products using both Shop API and Checkout API store fronts. This information is then forwarded to the provider used.

Required information

  • E-mail: which e-mail to notify. when Checkout API is used, this can be left out if customer has logged in.
  • Item: the item to be notified about.
  • ShipTo: country and if available state. since we allow for different warehouses to serve different parts of the world we need to know where the customer is so we only notify when item is available in this region.


  • Language: the language to use. When using Checkout API it will be taken from session if not provided.

Getting notified

When stock is added in Centra we will check if the modified item has any susbcribers waiting for notification and if so we tell the provider how much stock is available which allows them to send an appropriate amount of notifications. Keep in mind that Centra does not control when and how many notifications are sent. That mechanics is implemented and depends solely on the notification service provider.

You need to have as much FTA stock as the Minimum stock level. If you have less stock, Centra will not trigger a back-in-stock update for your product. Minimum stock value is 10 by default.

What about the old newsletter subscribe with products?

It is still possible to pass a product to our /newsletter-subscription endpoint. Once the user registers for the newsletter, Centra creates a subscriber with a special tag in Rule and adds product details fields. When the stock is replenished, a merchant is able to filter subscribers manually and send the notifications that way. It means there is no automation available when using this endpoint. It only remains for backwards compatibility with existing sites. For new sites use the new back-in-stock endpoints (eg. /back-in-stock-subscription .

E-mail providers with support for back in stock



  • Setup the E-mail trigger plugin for "Rulemailer v4"
  • Provide an API key
  • Set "Enable back in stock notifications" to "yes"

How to use

When a subscriber requests to be notified of an item the tag Rule - Waiting For Product Alert will be applied, and then when stock is updated and the subscriber should be notified the tag is replaced with Rule - Product Alert Triggered, theese tags can be used to setup automation for notifying your subscribers. Refer to Rule documentation for details. Centra syncronises stock with rule every 15 minutes and only if stock level of the product is above declared minimum.

Email templates used in the automation can use custom fields set for the notification. Fields are accessible in the template as CustomField:Rule-ProductAlert.<field_name>. Refer to the list below to see what data is available for back in stock email templates.

The fields that are available as localised will be separate fields named as the normal field followed by an _ and the language ISO 639-1 code. If the product has not yet been translated to this language this field will contain the unlocalised product name, making it always safe to use the localised field so long as the language remains active in Centra.


If you have German localisation configured and set in centra the field DisplayName_de will be available and will contain the german localised version of the display name. If you also have Spanish as language but have not yet added localisation for this the field DisplayName_es will be available and contain the same text as the DisplayName field.

Available Fields

Field name Contains Localized?
DisplayName Display name yes
DisplayUri Display URI yes
Brand Brand name no
DisplayImage first image for display in selected size, without domain no
Variant Variant name yes
Excerpt Short description yes
Description Description yes
SKU Product number + Variant number no
SizeSKU Size SKU no
Size Size name no
PriceInRegion Item price in subscribers region + currency, formated as defined in centra no
PriceInRegionAmount ietm price for subscribers region as a number no
CurrencyInRegion currency ISO code for subscribers region

Sending Notifications

Since it is Rule that contains the notification sending logic we encourage to familiarize oneself with Rule Product Alerts documentation. Centra does not control when and how many notifications are sent, but updates stock information for subscribed products in Rule.