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Inventory Easy ~15 min to build

Email your supplier when a product runs low

When a variant drops to your reorder point, send the supplier a reorder email with the SKU and current quantity, so you stop finding out from a customer.

Trigger: A product variant's inventory quantity changes and crosses your reorder threshold.

What it does

  1. Detect the inventory change
  2. Check it just crossed the threshold (so you email once, not on every sale)
  3. Email the supplier with SKU, product, current quantity

Tools involved: Shopify Flow · Make · n8n · Zapier · Gmail

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How to build it

Shopify Flow Recommended

Trigger: Product variant inventory quantity changed

Conditions

  • productVariant.inventoryQuantity is less than or equal to 5
  • AND inventoryQuantityPrior is greater than 5 (only fire on the crossing)
  • Optional: product.vendor equals "Acme Supply" to route per supplier

Actions

  1. Send internal email: To = supplier address, Subject = Reorder: {{product.title}} / {{productVariant.sku}}, Body includes {{productVariant.inventoryQuantity}}

Shopify publishes an official template for this: "Initiate reorder with vendor when inventory gets low". Use one workflow branch per vendor, or keep a vendor email in a product metafield.

Get it: Shopify Flow

Make

  1. Shopify > Watch events (advanced), Event topic INVENTORY_LEVELS_UPDATE
  2. Filter: available <= 5
  3. Shopify > Make a GraphQL API call: look up the inventory item's variant (SKU, product title)
  4. Gmail > Send an email

The inventory webhook carries IDs, not names, so the GraphQL lookup is needed for a readable email.

Build it in Make

n8n

  1. Shopify Trigger, topic inventory_levels/update
  2. IF: available <= 5
  3. HTTP Request (Shopify credential): GraphQL query for the inventory item's variant
  4. Gmail: Send

Build it in n8n

Zapier

  1. Shopify: Updated Inventory
  2. Filter by Zapier: quantity less than 6
  3. Gmail: Send Email

Build it in Zapier

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