Automating Pre-Order Inventory and Arrival Dates on Shopify

Overview

For high-performing eCommerce operations, keeping customers informed while avoiding operational friction is crucial—especially when dealing with incoming stock and pre-orders. One Shopify merchant approached me with a challenge: they needed a way to automate inventory updates and arrival date messaging for products that were on the way but not yet received.

Using Shopify's Admin API and Stocky's Purchase Order data, I built a custom automation system that helped them manage pre-orders at scale, improve customer transparency, and eliminate manual work.

The Challenge

The client's inventory was spread across multiple Shopify locations:

• Retail store
• Warehouse
• Pre-Order location (for items in transit)

The problem? Shopify doesn't natively expose "available" inventory per location or allow dynamic syncing of Stocky's expected delivery data to the storefront. That meant:

• Manual tracking of POs and variant quantities
• No way to display "arrival dates" for pre-orderable products
• Operational risk due to overselling or outdated stock info

The team needed a system that would automatically track changes to incoming inventory, update Shopify's available stock for the Pre-Order location, and reflect expected delivery dates—all without human intervention.

Solution Design

I built a custom Node.js app that runs every 30 minutes (or on demand) and fully automates their pre-order logic:

Syncing Stocky POs to Shopify

• Pulls all active purchase orders from Stocky
• For each variant with an incoming quantity > 0, the app:
  • Updates the Pre-Order location's available quantity
  • Sets a variant-level arrival date metafield
• When incoming quantity drops to 0 (e.g., after PO receipt or cancellation):
  • Resets the Pre-Order quantity to zero
  • Deletes the arrival date metafield

Enabling Safe Pre-Orders

• While items are in the Pre-Order location, Shopify can sell them as long as stock exists
• Shopify's inventory system prevents overselling by respecting location-level available stock

Post-Arrival Logic

• When stock is marked "Received" in Stocky:
  • Shopify automatically moves the inventory to the destination location
  • The app clears out pre-order inventory and arrival dates to reflect the live state

Technical Highlights

• Shopify Admin API usage: for precise updates to variant inventory and metafields
• Stocky API integration: for accurate PO and delivery date syncing
• Rate-limit protection: delays applied to avoid API throttling
• Batch processing: handles hundreds of variants efficiently
• Manual override support: via a secure POST /preorder endpoint

Tech Stack

Results

The automation delivered clear wins across the board:

"We no longer have to touch a single setting after placing a PO. The storefront just updates itself."

Why It Matters to eCommerce Managers

If you're responsible for:

• Site accuracy
• Customer satisfaction
• Operational alignment with logistics and marketing

…then a pre-order automation system like this one frees up your team to focus on growth, not repetitive admin work. It supports:

• Seamless customer experiences
• Smarter inventory management
• Reduced operational overhead