## Introduction
Managing inventory efficiently is critical for startups and small businesses to avoid stockouts, manage assets, and maintain customer satisfaction. Airtable offers a user-friendly Inventory Tracker feature, but it can become costly as your user base or data volume grows. This article presents a detailed, technical guide on building an Inventory Tracker automation using n8n, an open-source workflow automation tool, that replicates and extends Airtable’s Inventory Tracker functionalities while saving on subscription costs. This workflow benefits operations specialists, startup teams, and automation engineers aiming to build scalable and customizable inventory management systems.
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## Tools and Services Integrated
– **n8n:** The core automation engine to build the inventory workflow.
– **Google Sheets:** To store and update inventory data as a low-cost, flexible database alternative.
– **Gmail:** For notifications when stock levels are low or replenishment is needed.
– **Slack:** To send real-time alerts to the operations or sales teams.
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## What Problem Does This Automation Solve?
Airtable’s Inventory Tracker is ideal for managing product stock or assets but can be expensive at scale. This automation provides:
– Centralized inventory data storage using Google Sheets.
– Automated stock level monitoring.
– Alerting and notification mechanisms for low stock.
– Easy modification and extension possibilities.
The main beneficiaries are inventory managers, operations teams, and startups looking to optimize costs and maintain real-time inventory visibility.
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## Workflow Overview
The automation workflow consists of:
1. **Trigger:** Scheduled workflow runs daily/hourly to check inventory status.
2. **Google Sheets Read:** Load current inventory data.
3. **Condition Check:** Evaluate stock levels against thresholds.
4. **Alerting:** Send notifications via Gmail and Slack for low inventory.
5. **Update Inventory:** Optionally update stock based on sales or receive data from upstream systems through API/webhook.
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## Step-by-Step Build Guide
### Step 1: Set Up Google Sheets Inventory Database
1. Create a Google Sheet with the following columns:
– **Product ID**
– **Product Name**
– **Stock Quantity**
– **Reorder Threshold** (minimum stock before restock alert)
– **Last Updated**
2. Populate initial inventory data.
3. Share the sheet with your n8n service account email for API access.
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### Step 2: Configure n8n Credentials
1. Create credentials in n8n for Google Sheets, Gmail, and Slack.
2. For Google Sheets, enable Google Sheets API and OAuth consent.
3. For Gmail, create OAuth credentials or use SMTP.
4. For Slack, create a Bot and get an API token with message sending permissions.
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### Step 3: Create the Scheduled Trigger Node
– Use the **Cron** node in n8n.
– Set schedule to run daily at a preferred time (e.g., 9 AM) or multiple times depending on inventory refresh needs.
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### Step 4: Read Inventory Data from Google Sheets
– Add the **Google Sheets > Read Rows** node.
– Connect it to the Cron trigger.
– Configure to target your inventory sheet.
– Set reading range to include all existing rows.
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### Step 5: Filter Products with Low Stock
– Add a **Function** node after reading rows.
– Use the following JavaScript code to filter products where Stock Quantity <= Reorder Threshold:
```javascript
return items.filter(item => {
const stockQty = parseInt(item.json[‘Stock Quantity’], 10);
const reorderThresh = parseInt(item.json[‘Reorder Threshold’], 10);
return stockQty <= reorderThresh;
});
```
- This returns only the products that require restocking.
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### Step 6: Send Email & Slack Alerts
- Add **Gmail > Send Email** node:
– Connect to filtered function node.
– Compose an alert email summarizing low-stock products.
– Include product name, current stock, and reorder threshold.
– Add **Slack > Send Message** node:
– Also connect to the filtered function node.
– Send a channel or direct message alert.
– Use markdown formatting for clarity.
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### Step 7: Optional – Update Inventory Based on Sales or Restock
– You can add a **Webhook** node to receive real-time stock updates from your sales system.
– Use **Google Sheets > Update Row** node to adjust inventory quantities accordingly.
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## Common Errors and Tips
– **Google Sheets API Limits:** Google Sheets has API call limits; batch updates and reads when possible.
– **Time Zones:** Make sure time zones in Cron triggers match your business timezone.
– **Ensure Data Consistency:** Validate data types in the Google Sheet; formulas or API writes can cause invalid data.
– **Slack Rate Limits:** Avoid sending too many alerts; aggregate multiple low-stock items into a single message.
– **Error Handling:** Utilize n8n’s error workflows to catch failures and retry or alert admins.
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## Scaling and Adaptation
– For larger inventories, consider integrating databases like PostgreSQL with n8n for more robust data storage.
– Extend the workflow to handle purchase order creation by integrating with purchasing systems or CRMs.
– Add user authentication or role-based access for modifying inventory data securely.
– Incorporate barcode scanner inputs by connecting n8n to mobile apps with Webhook triggers.
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## Summary and Bonus Tip
By building this Inventory Tracker automation using n8n and Google Sheets, you achieve a low-cost, customizable, and scalable system that reduces dependency on expensive SaaS tools like Airtable. The workflow provides actionable notifications to keep your stock optimized, ensuring operations run smoothly.
### Bonus Tip:
Implement a slack interactive message with buttons to “Acknowledge” or “Order Stock” that triggers additional workflows in n8n, enabling an interactive inventory management experience directly from Slack.