Most small businesses don’t need a dedicated inventory management system — they need their existing Google Sheet to actually warn them before something runs out. Discovering you’re out of stock because a customer told you is one of the more avoidable ways to lose a sale.
This guide uses Make instead of n8n on purpose — inventory alerting is exactly the kind of lighter, lower-module workflow where Make’s visual builder and credit-based pricing work in your favor. See our n8n vs Make comparison if you’re deciding which tool fits your broader stack.
The Alert Architecture
[ Scheduled Trigger (e.g. every morning) ]
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[ Read Inventory Sheet Rows ]
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[ Filter: Stock Below Threshold ]
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[ Send Low-Stock Alert ] [ Update "Last Alerted" Column ]Step 1: Structure Your Inventory Sheet
Before building anything, make sure your sheet has clear columns to work with: Product Name, SKU, Current Stock, Reorder Threshold, and Last Alerted. That last column matters more than it looks — without it, you’ll get the same low-stock alert every single day until you restock, which trains you to ignore the alert entirely.
Step 2: Set the Scheduled Trigger
In Make, add a scheduled trigger module to run once a day — early morning works well, so you know your stock position before the day’s orders start coming in.
Step 3: Read and Filter Inventory Rows
Add a Google Sheets “Search Rows” module to pull your inventory data, then a Filter module immediately after it with the condition: Current Stock is less than Reorder Threshold. Only rows that actually need attention continue further down the scenario — everything else stops here, which is what keeps this workflow cheap on Make’s credit-based pricing.
Step 4: Send the Alert
Route the filtered rows to whichever channel you actually check daily:
- Email: a simple digest listing every product currently below threshold.
- Slack: a message per low-stock item, useful if multiple people need visibility.
- SMS: for the handful of products where running out is a genuine emergency, not just an inconvenience.
Step 5: Prevent Repeat Alerts
After sending an alert, update that row’s “Last Alerted” column with today’s date. Add a second filter condition checking that the last alert wasn’t sent today (or within the last N days, if you’d rather space them out) so the same low-stock item doesn’t spam you every single morning until it’s restocked.
Optional: Auto-Draft a Purchase Order
Once the basic alert is reliable, a natural next step is having Make draft a reorder email to your supplier automatically — pre-filled with the product name and a suggested reorder quantity — landing in your drafts folder ready for a final review before you hit send.
The Bottom Line
This is a genuinely small workflow — four or five modules — and one of the fastest to pay for itself. A single prevented stockout on a popular product usually covers months of whatever automation tool you’re running it on.