By Luciano Vannelli

Bare Necessities · Shopify architecture design for backorder migration

Bare Necessities is a US-based lingerie retailer on Shopify Plus doing over $3M in annual revenue. When they decided to end their relationship with their previous technology provider, they faced a hard deadline: the provider was cutting off services and taking their custom code with them.

I was brought in to analyze the situation and design the path forward.

The first challenge was understanding what was actually running on the store. The previous provider hadn't shared their codebase. The theme contained minified JavaScript with Vue.js patterns, something between a standard theme and a headless setup. I reverse-engineered the store to map out every custom behavior, identify what was going to break when the provider left, and prioritize what needed to be rebuilt.

The most critical piece was backorder and preorder. Roughly a third of their catalog, over 100,000 variants across a large lingerie assortment, was being sold on backorder. The logic for this had lived entirely in the previous provider's middleware. Their ERP, Movex, and WMS, Barrett, had no native backorder support. When the provider left, that functionality was going to disappear.

I designed the full Shopify-native architecture to replace it. A dedicated inventory location for backorder stock, set last in Shopify's location priority so it only activates when real warehouse stock is exhausted. Theme customization to surface the ETA per product, pulled from a metafield updated by the integration rather than a hardcoded static message. Cart line item properties to flag backorder items for downstream processing. Checkout Extensions to show backorder information clearly before the customer pays. Shopify Flow to tag backorder orders automatically so the fulfillment team could route them correctly.

The integration work itself was handled by Techsera, an external team without Shopify expertise. I advised them on the correct Shopify APIs and endpoints to use, the data model they needed to write to, and how to structure the sync so the backorder logic would work correctly end to end.

The project ran under deadline pressure with a store doing serious volume and no margin for downtime.

Bare Necessities System Integration Architecture - Part 1
Bare Necessities System Integration Architecture - Part 2
Shopify Preorder & Backorder Migration Flow