Guides · Choosing a tool
Low stock alerts vs back in stock alerts: which one did you actually search for?
Two Shopify features with almost the same name do opposite jobs. One emails you so you can reorder, the other emails your customer so they can buy. Here is how to tell which you need, and what each one costs.
Search the Shopify App Store for "stock alerts" and you get two categories of app mixed together. They sound alike, they are priced alike, and they solve opposite problems. A lot of merchants install the wrong one, notice a month later that nothing improved, and conclude that inventory apps do not work.
The distinction is one question: who receives the email?
Low stock alerts — the email goes to you
Also called: low inventory alerts, restock alerts, reorder alerts, inventory notifications.
The purpose is to reorder in time. Something tells you a variant is running down while there is still enough runway to place a purchase order and receive it.
- Recipient: you, or your operations person.
- Fires when: stock falls below a level you set, or below a number of days of cover.
- What it saves: the sales you would have lost while out of stock, and the panic freight you would have paid to avoid that.
- Free version: Shopify Flow's Get notified by email when product variant inventory is low template, included on every Shopify plan.
Search that leads here: "shopify low stock alert", "shopify low inventory alert", "shopify reorder point", "shopify restock notification for admin".
Back in stock alerts — the email goes to your customer
Also called: notify me when available, restock notifications, waitlist, sold-out signup.
The purpose is to recover a sale you already lost. A customer lands on a sold-out product, leaves their email, and gets a message the moment it is available again.
- Recipient: the customer.
- Fires when: a sold-out variant goes back above zero.
- What it saves: the customer who would otherwise have bought from someone else and never returned.
- Free version: Shopify Flow has a Product variant back in stock trigger, but collecting the signups needs a storefront widget, so this one genuinely wants an app.
Search that leads here: "shopify out of stock notification", "shopify notify me when available", "shopify back in stock app", "shopify waitlist".
They are not alternatives
The uncomfortable part: if you only install the customer-facing one, you are building a list of people who wanted the thing you did not have. That list is worth something, and it is still a list of people you disappointed.
The two work as a pair, in this order:
- Low stock alerts so you run out less often.
- Back in stock alerts to catch the times you run out anyway.
If you can only do one this month, do the first. It is free with Shopify Flow, and it reduces the number of customers who ever see the sold-out page.
A third thing people mean: "Only 3 left" on the product page
Neither of the above. That is a scarcity display in your theme, driven by
variant.inventory_quantity in Liquid, and most modern themes have a setting for it in
the product section of the theme editor. No app, no email, no alert.
What we build, and what we do not
StockPilot is the first kind. It emails you when a variant drops below the level you set, per location, based on real sales velocity, and it deliberately does not send one email per unit sold. It has a free plan; it is $9/month after that.
It does not do back-in-stock notifications to customers, and we are not planning to. If that is what you came for, the App Store category to search is "back in stock" — several mature apps do it well, and sending you to one of them costs us less than selling you the wrong tool.
Related
- Shopify low stock alerts: the free way, and the four places it breaks
- How to set a reorder point in Shopify
Shopify Flow template and trigger names checked on 2 August 2026.