You check your Shopify dashboard. Three products are out of stock and you didn’t know. Meanwhile, 47 people tried to buy them in the last week. They saw “Sold Out” and left.
Stockouts are a silent revenue killer. Customers don’t wait. They find another store. And they don’t come back.
Shopify Flow can fix this. It’s a free automation tool built into Shopify (available on Basic plans and above) that runs triggers and actions without any code. The low-stock alert is the simplest automation you can build, and it pays for itself the first time it saves a sale.
What You Need
- A Shopify store on the Basic plan or higher
- Shopify Flow installed (free from the Shopify App Store)
- 10 minutes
Step 1: Open Shopify Flow
Go to Apps, then Shopify Flow in your Shopify admin. If you’ve never used it, you’ll see a blank workspace. Click “Create workflow.”
Step 2: Set the Trigger
Click the trigger node and select:
Trigger: “Inventory quantity changed” (under “Inventory” triggers)
This fires every time your stock level changes, whether from an order, a manual update, or a restock.
Step 3: Add a Condition
Click the “+” after the trigger and add a condition:
Condition: “Inventory quantity” “is less than or equal to” [your threshold]
Set your threshold. For fast-moving products, use 10. For slower ones, use 5. You can create separate workflows for different product types later, but start simple.
Make sure you’re checking the “current inventory quantity” at the product variant level, not the product level. Variants (like size or colour) are what actually go out of stock.
Step 4: Add the Action
Click the “+” after the condition and add an action:
Action: “Send email” (under “Actions”)
Fill in the fields:
- To: Your email address (or your operations person’s email)
- Subject: “Low stock alert: {{product.title}} – {{variant.title}}”
- Body: Something like:
“{{product.title}} ({{variant.title}}) has dropped to {{inventory_quantity}} units. Time to reorder. Product link: {{product.admin_url}}”
The double curly braces are Shopify Flow variables. They pull real data from the trigger event. Don’t skip them. They’re what make this email actually useful.
Step 5: Test and Activate
Click “Test workflow” in the top right. Shopify will run the trigger against your most recent inventory change to see if the conditions match.
If the test email arrives with the right product name and stock level, you’re done. Click “Turn on” in the top right.
What This Actually Does
From now on, every time a product variant drops to your threshold or below, you get an email with the exact product, variant, current stock, and a direct link to the product admin page. No dashboard checking. No guessing.
You can extend this later:
- Add a Slack notification action for real-time alerts
- Add a “Tag product” action so you can filter low-stock items in your admin
- Add a “Reorder from supplier” template email that pre-fills your supplier contact
But start with the email. It takes 10 minutes and it works.
One More Thing
If you’re running ads on products that go out of stock regularly, pair this with a second Flow that automatically pauses ad campaigns when inventory hits zero. There’s no point paying for clicks on a “Sold Out” page.
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