Shopify Stock Reservation System
We launched a public Shopify application that provides merchants with timed cart reservations to reduce abandoned carts and improve inventory accuracy.
Technologies used:
16 Dec 2025
Germany
The Vision & Challenge
Our partner, an e-commerce software developer, identified a specific point of failure in high-volume online stores. Their goal was to build and launch a Micro-SaaS application on the Shopify App Store, creating a new, recurring revenue stream.
The central problem was inventory paralysis caused by abandoned carts. When a customer adds a high-demand, low-stock item to their cart but does not check out, that item is functionally removed from sale. This results in lost sales from other interested buyers and creates inaccurate stock levels, a critical issue for any merchant.
Robust Devs was engaged to design and build the complete application from the ground up. We developed a system that integrates directly with Shopify to place a temporary, timed hold on items in a customer's cart. This creates fair urgency for the buyer and automatically returns the inventory to the public pool if the sale is not completed.
Project challenges
- Maintaining perfect, real-time data synchronization between the storefront cart, our application's backend, and Shopify's inventory system was essential.
- The frontend timer component had to be injected and function correctly across thousands of unique Shopify themes without manual configuration by the merchant.
- The system required a flexible rules engine, allowing merchants to set different reservation durations for different tiers of customers.
Solutions
- We built a Laravel backend that utilizes Shopify’s Draft Order API and webhooks. This creates a reliable, two-way sync that reserves inventory and reflects any cart changes, whether made by the customer or the admin.
- A theme-agnostic JavaScript module was written to intelligently scan the store’s DOM and place the countdown timer in the correct location on cart and product pages, ensuring wide compatibility.
- We developed a merchant-facing admin panel using Shopify Polaris. Inside, merchants can create rules that link reservation times to specific customer tags, enabling custom sales strategies for VIPs or first-time buyers.
Technologies used
We are concerned about the security and performance of our customers. That's why we always keep updating and use best technologies in our products
Front-end
JavaScript
ReactJS
HTML5
CSS3
Back-end
PHP
Laravel
DevOps
Linux
Digital Ocean
Database
MySQL
Real-Time Inventory Reservation
When a customer adds an item to their cart, our system instantly communicates with the Shopify Draft Order API to provisionally reserve that unit. This action removes it from the public-facing stock count, preventing overselling and giving the merchant an accurate, real-time view of available inventory.
Tiered Reservation Timers
The application allows merchants to define unique reservation windows based on Shopify's native customer tags. A store owner can set a longer timer for a VIP customer and a shorter one for a new visitor. This gives merchants a granular tool to manage demand and reward customer loyalty.