n8n Inventory Sync Shopify Amazon Flipkart via Google Sheets + Slack Alerts

Keep Shopify, Amazon, and Flipkart inventory perfectly in sync—using Google Sheets as the master ledger and Slack for instant alerts

This n8n workflow automatically syncs a single, unified inventory count across Shopify, Amazon (SP-API), and Flipkart every 10 minutes. It uses Google Sheets to track inventory and order processing, applies a safety buffer to calculate sellable quantities, updates channel availability, and posts low-stock, out-of-stock, oversold, and failure alerts to Slack.

What this workflow does

• Scheduled sync (every 10 minutes): Reads the last orders cursor from Google Sheets and uses an overlap window to avoid missing updates.
• Loads inventory sources: Pulls the Inventory Master, the Processed Lines ledger for deduplication, and any pending manual stock adjustments.
• Fetches order/shipment changes: Retrieves updated orders from Shopify (GraphQL), fetches updated Amazon line items via SP-API (using an LWA token), and pulls Flipkart pre-dispatch and cancelled shipments.
• Computes sellable quantity: Calculates per-SKU stock movements, applies cancellations and queued adjustments, and subtracts each SKU’s safety buffer to determine sellable inventory.
• Updates only what changed: Pushes updated sellable quantities to Shopify, Amazon listing availability, and Flipkart inventory—or performs a nightly full sync when required.
• Ledger + state updates: Writes SKU totals back to the Inventory Master, appends new ledger entries to Processed Lines, marks adjustments as applied, and saves the new cursor (Sync State).
• Slack alerts: Sends alerts for oversold/out-of-stock/low-stock SKUs (including recent sales velocity and days of cover) and posts a separate Slack alert if any run fails.

Use cases

• Prevent overselling by keeping sellable stock accurate across multiple sales channels.
• Use Google Sheets as a human-editable inventory control center with audit-ready ledgers.
• Monitor health of your inventory sync with Slack notifications for both stock risk and workflow failures.

Technical details

• n8n nodes: if, code, slack, sticky note, form trigger, http request
• Integrations: Google Sheets (Inventory Master, Processed Lines, Sync State), Shopify (GraphQL), Amazon SP-API (LWA token), Flipkart (pre-dispatch + cancelled shipments), Slack alerts