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Out of stock notifications on Shopify

Those three words cover two completely different jobs and the apps that do them are not the same apps. Work out which one you need first. Installing the wrong kind is a common and easily avoided mistake.

By Fazeel Tanveer, Founder · Last reviewed 20 August 2026

Two different jobs

This page is about the second one. Both are worth having, in that order, because stopping the problem is cheaper than fixing it.

On this page

  1. An out of stock alert always arrives too late
  2. How to set up the alert to your own team
  3. Available stock is not the same as on hand stock
  4. Then tell the customer too

An out of stock alert always arrives too late

By the time stock hits zero the damage is done. Nobody can buy the product, your ads may still be spending on it and shoppers are already hitting the sold out button.

It is still worth having, because a zero nobody spots can sit there for weeks. Just treat it as the safety net rather than the main defence. The alert that saves you money fires while there is still stock on the shelf and time to act.

In practice that means running both. A low stock alert set from your restock time is the real warning. An out of stock alert catches anything that slipped past it.

How to set up the alert to your own team

With Shopify Flow, free on paid plans:

  1. Create a workflow on the inventory quantity changed trigger.
  2. Add a condition on productVariant/inventoryQuantity equal to 0 for the out of stock case, or less than or equal to your threshold for the earlier warning.
  3. Send an internal email to the people who can act on it.

With an alerts app: both cases are usually just settings rather than two separate builds and each location is checked on its own.

Watch the continue selling setting. A variant set to keep selling when out of stock drops past zero into negative numbers instead of stopping at zero. A condition that checks for exactly 0 can miss it completely. Check for less than or equal to 0 instead.

Available stock is not the same as on hand stock

Shopify keeps several different stock counts. Pick the wrong one and your alerts will look wrong to everybody reading them.

A product can show plenty on hand and still have zero available, because every unit is promised to an order you have not shipped. Watching on hand hides that completely and that is exactly the case you needed to hear about.

Then tell the customer too

Once your own team is covered, a back in stock notification on the product page wins back sales you would otherwise lose. It is a different kind of app and it is worth having, but it comes second. It recovers a sale you already missed, where the alert to your team stops you missing it.

Catch it before zero

Stockwell alerts on low stock and on out of stock, per location, so the early warning and the backstop are both covered without building a workflow for each.

Get it on the Shopify App Store Free plan covers 50 SKUs with a daily summary. Paid plans add instant alerts and more recipients. No card needed to start.

Common questions

How do I get notified when a product is out of stock on Shopify?

Build a Shopify Flow workflow on the inventory quantity changed trigger, with a condition that checks for zero or below. Or use a low stock alerts app. Shopify never sends this email on its own.

What is the difference between a back in stock alert and an out of stock alert?

A back in stock alert goes to a shopper who asked to hear when an item returns. An out of stock alert goes to your own team to say something needs reordering. Different apps, different job.

Should I alert at zero or before?

Before. At zero the sale is already gone. Set your main alert from how long a restock takes, then keep the zero alert as a safety net for anything that slipped past it.