Engineering Stupell Wall Art's Custom Shopify Store & Amazon Inventory, Order & Tracking Sync
“Parallel Loop built our custom Shopify theme and the Amazon bridge we needed. Prices and stock stay in sync, Amazon orders land in Shopify, and tracking goes back automatically when we ship.”
Stupell Wall Art (Stupel Wall Art) is an ecommerce brand selling wall art on its own website and on Amazon. The direct-to-consumer channel runs on Shopify, while Amazon extends reach to marketplace shoppers. Parallel Loop built both the customer-facing store and the automation layer that keeps catalog, inventory, orders, and shipments aligned across channels.
The Product Challenge
Stupell needed a branded Shopify experience plus reliable Amazon operations without double entry on every SKU. Wall art catalogs carry many variants, frequent stock changes, and seasonal pricing updates. When Amazon listings drift from Shopify, overselling and support tickets follow. Orders placed on Amazon must appear in Shopify for fulfillment workflows the team already uses, and carriers' tracking numbers must post back to Amazon automatically once packages ship. The merchant required a custom theme that showcases artwork collections while a background sync service handles SP-API complexity.
- Generic Shopify Theme Limitations
- Amazon Stock Updated by Hand
- Marketplace Orders Re-Keyed in Shopify
- Tracking Uploaded Late to Amazon
- Risk of Overselling Across Channels
- Custom Shopify Theme on stupell.com
- Shopify to Amazon Price & Inventory Push
- Amazon Orders Pulled into Shopify
- SP-API Tracking on Fulfillment
- Node.js Sync on AWS EC2 + Agenda Jobs
Phase 1: Custom Shopify Website & Catalog Experience
We developed the complete Shopify website on a custom theme built for wall art merchandising. Our Shopify developer paired with a full-stack engineer to design collection layouts, variant selectors for sizes and finishes, and performance-tuned product galleries. The theme keeps brand presentation consistent while remaining maintainable for merchandising updates without developer intervention on every campaign.
Our specialized Shopify and ecommerce tooling team and custom software development pod extended storefront capabilities with supporting Next.js and React.js surfaces where marketing and operational tools required richer interaction than Liquid alone.
Phase 2: Amazon Connector (Inventory, Orders & Tracking)
We created a complete integration system connecting Amazon and Shopify as the operational source of truth. When merchants update price or quantity in Shopify, the connector propagates changes to linked Amazon listings so marketplace availability mirrors the primary catalog. Amazon orders ingest into Shopify through scheduled and event-driven jobs so warehouse staff fulfill from one queue.
When an order is fulfilled, tracking numbers flow back to Amazon through Amazon SP-API, closing the loop for buyer notifications and marketplace performance metrics. The sync service runs on Node.js and Express.js with PostgreSQL for order state, MongoDB for integration logs, and Agenda Jobs on AWS EC2 for retries, rate-limit aware SP-API calls, and idempotent updates.
- Catalog sync: Export Shopify price and stock to Amazon listings.
- Order import: Pull Amazon purchases into Shopify for fulfillment.
- Shipment confirm: Post carrier tracking to Amazon after pack and ship.
- Observability: Job logs and failure retries for peak sale periods.
Quantified Business Outcomes
Stupell now sells wall art on a custom Shopify storefront while Amazon stays synchronized on inventory, orders, and tracking.
| Performance Metric | Before Parallel Loop | Stupell Integrated Stack |
| Shopify Storefront | Off-the-shelf theme constraints | Custom Theme Built for Wall Art |
| Amazon Inventory | Manual spreadsheet updates | Automated Price & Stock Push from Shopify |
| Amazon Orders | Re-entered by hand | Imported into Shopify Automatically |
| Shipment Tracking | Delayed marketplace uploads | SP-API Tracking on Fulfillment |
Technical Deep-Dive: Frequently Asked Questions
Why is Shopify the source of truth for price and stock?
Stupell merchandising teams already manage collections, variants, and promotions inside Shopify Admin. Pushing updates outbound to Amazon prevents conflicting edits on two masters and keeps Amazon listings accurate whenever a SKU sells down on the web store.
How are Amazon orders represented in Shopify?
The connector maps Amazon line items to Shopify products and creates orders with channel tags so fulfillment staff can filter marketplace volume. Inventory reservations decrement the same pools synced to Amazon, reducing oversell risk during flash promotions.
What SP-API steps run after shipment?
When Shopify marks an Amazon-sourced order fulfilled, Agenda Jobs call Selling Partner shipment confirmation endpoints with carrier and tracking identifiers. Failed posts retry with backoff so temporary quota limits do not strand customers without tracking emails from Amazon.
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