Your line stopped on a Tuesday. Not because the material wasn't ordered. Because nobody saw the stockout coming until the floor called the office asking where the parts were.

A 40-person manufacturer we worked with had this problem every few weeks. Their inventory tracking lived in a Google Sheet — updated manually on Fridays by the warehouse lead. By Tuesday, the numbers were five days stale. When a high-demand job ran hot, nobody knew until a supervisor walked over and found the bin empty.

We built them an automated inventory alert and purchase order system using n8n. It took under an hour. It runs every morning at 6 AM. They haven't had an unplanned production stop in two months.

Here's exactly what we built and how you can do the same.

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The Problem With Manual Inventory Checks

Most small manufacturers track inventory one of two ways: someone walks the floor and counts, or someone looks at a spreadsheet that was last updated whenever the warehouse person had time.

Both methods have the same failure: they're reactive. By the time you know you're low, you're already behind. Lead times don't care that you checked last week.

The fix isn't an expensive inventory management system or an ERP upgrade. It's connecting the data you already have to an automated watchdog that runs on a schedule — and alerts you before you're in trouble.

n8n is the right tool for this. It's a workflow automation platform that connects your apps and runs logic on a schedule. You can self-host it (your data stays on your servers) or run it in the cloud for about €20/month. It has a visual workflow builder your office manager can learn without an IT degree. And critically: it can read from a Google Sheet or Excel file your team already uses.

No ripping out your existing process. No new software for the warehouse. Just automation layered on top of what you already have.

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What the Workflow Does

Here's the workflow we built for this 40-person shop:

Every morning at 6 AM, n8n:

1. Reads the inventory sheet (Google Sheets in their case — works with Excel too)
2. Filters every row where the current quantity is below the reorder point
3. For each flagged item, builds a pre-filled PO draft: supplier name, part number, reorder quantity, standard unit cost
4. Sends an alert to the purchasing manager's email with the flagged items and draft POs attached
5. Pings the #purchasing Slack channel with a summary

The purchasing manager shows up at 7:30 AM, reviews the alert, approves or adjusts the drafts, and sends POs before the first shift starts. The whole review takes under 30 minutes. Before this workflow, the process was a 4–5 hour weekly audit that still missed things between checks.

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How to Build It: Step-by-Step

You'll need: n8n (cloud or self-hosted), access to your inventory spreadsheet (Google Sheets or Excel), your suppliers' contact information, and a Slack workspace if you want the channel ping.

Step 1: Set up a Schedule trigger

In n8n, create a new workflow and add a Schedule trigger node. Set it to run daily at your preferred time — we use 6 AM so alerts are ready before the first shift.

Step 2: Connect to your inventory sheet

Add a Google Sheets node (or Microsoft Excel node if you use Excel/OneDrive). Connect it to your inventory workbook and select the sheet where you track stock. You'll need to authenticate n8n to your Google or Microsoft account — this is a one-time setup that takes about five minutes.

Map these columns: Item Name, Part Number, Current Quantity, Reorder Point, Preferred Supplier, Standard Order Quantity, Unit Cost.

If your sheet doesn't have a Reorder Point column yet, add one. This is the quantity below which you want an alert. For most shops, this is 1–2 weeks of usage based on typical demand.

Step 3: Filter for items below reorder point

Add a Filter node. Set the condition: Current Quantity is less than Reorder Point. This node passes only the items that need attention — everything else gets dropped.

Step 4: Build the PO draft

Add a Set node to build the PO data for each flagged item. Calculate order quantity (Standard Order Quantity minus Current Quantity, or just Standard Order Quantity if you prefer to reorder in full batches). Calculate total cost (Unit Cost × Order Quantity). Format the date.

Add a Code node if you want to generate a formatted PO text block for each item — this is a few lines of JavaScript that loops through the items and builds a readable summary. n8n has a built-in AI assistant that can write this code for you if you describe what you want.

Step 5: Send the email alert

Add a Gmail or SMTP node. Set the recipient to your purchasing manager's email. Use a simple subject line: "Daily Inventory Alert — {number} items below reorder point — {date}." In the body, paste the PO draft block you built in Step 4. Clear, actionable, nothing buried.

Step 6: Ping Slack (optional but useful)

Add a Slack node. Point it at your purchasing or ops channel. Send a one-line summary: "Inventory check complete. 3 items flagged. Review your email." Takes 60 seconds to add and means the right people see it even if they miss the email.

Step 7: Test and activate

Run the workflow manually once to verify it reads your sheet, filters correctly, and sends the alert. Review the email to confirm the PO drafts look right. Activate the workflow. Done.

Total build time: under an hour for someone who's used n8n before. Budget two hours if this is your first workflow — most of that time is authenticating to Google Sheets and formatting the email the way you want it.

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Results After Two Months

Here's what that 40-person shop saw after running this workflow:

• Manual weekly inventory audits replaced by automated daily checks — the warehouse lead stopped spending Friday afternoons counting and entered data updates on an as-needed basis instead
• Shortages surfaced 5–7 days earlier on average — the daily check caught trends that the weekly count missed
• Monthly PO admin time dropped from 4–5 hours to a 30-minute daily review — drafts were already prepared, the manager just approved and sent
• Zero unplanned production stops in the two months after deployment — compared to two or three per month before

That last number is the one that matters. Unplanned stops cost time, expedite fees, and customer trust. A workflow that runs every morning and takes 30 minutes to review is a cheap insurance policy against all of that.

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What This Doesn't Do (And Why That's Fine)

This workflow is a quick win. It's designed to be built by one person in under an hour and deliver immediate, measurable value. It does not:

• Sync bidirectionally with your ERP
• Route PO approvals through a multi-step chain
• Trigger dynamically based on production demand signals
• Handle vendor substitutions when a supplier is out of stock
• Track goods received and auto-update inventory on receipt

Those are architecture-level problems. When you're ready to tie this into your ERP, trigger alerts based on production schedules rather than fixed reorder points, and build multi-step approval workflows — that's when the design conversation matters.

This is step one. It proves that the workflow works and that your team will use it. Once you've seen the daily alert become part of your morning routine and watched the unplanned stops disappear, you'll have a clear picture of what to build next.

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The Bigger Picture

The Home Depot rule applies here: just because you have every tool to build a house doesn't mean you can build a beautiful house. n8n has every tool. But knowing which workflow to build, how to connect it to your ERP without breaking your existing data model, and how to design it so your team can maintain it when you're not around — that's architecture.

This inventory alert is a single workflow with a single trigger and a simple output. It works because it's narrow. When you start connecting five workflows across your purchasing, scheduling, quality, and customer communication systems, the design decisions compound. That's where shops run into the 12-month wall — everything worked in isolation, then nothing worked together.

We help manufacturers figure out where to start, what to connect next, and how to build it so it doesn't fall apart at month nine.

If you're ready to start, the inventory alert above is a good first hour. When you're ready to connect it to everything else — book a discovery call at cloudbeast.io/schedule.