Multi-marketplace e-commerce sync engine with Amazon, Walmart & WooCommerce.
Project Overview
WholeCell.io is an inventory and order management platform designed to unify selling across multiple e-commerce marketplaces. As a core team member, I built the customer portal, integrated three major marketplace APIs, and delivered comprehensive test coverage across the platform.
The Problem
E-commerce sellers waste enormous time manually syncing orders and inventory across Amazon, Walmart, and WooCommerce. WholeCell needed a reliable, real-time sync engine that could handle marketplace-specific quirks, rate limits, and data format differences — all without disrupting the seller's workflow.
Marketplace Integrations
Amazon
Selling Partner API — Orders, Inventory, Fulfilment sync
Walmart
Marketplace API — Orders, Inventory bidirectional sync
WooCommerce
REST API — Products, Orders, Returns sync
My Responsibilities
Customer Portal
Built a full customer portal where customers can place orders, track them, and process payments — the primary revenue-generating surface.
Amazon SP API
Integrated Amazon Selling Partner API to sync a seller's orders, inventory, and fulfilment data in real-time.
Walmart Marketplace API
Integrated Walmart Marketplace API to bidirectionally sync orders and inventory with Walmart's marketplace.
WooCommerce API
Integrated WooCommerce REST API to sync products, orders, and returns from WordPress-based storefronts.
Test Coverage
Wrote comprehensive RSpec test suites covering all three integrations and added coverage for pre-existing features.
Architecture & Performance
Provided OOP methodology guidance, recommended architectural improvements, and optimised system performance proactively.
Key Challenges & Solutions
Marketplace API Rate Limits
Each marketplace's API has unique rate limits and throttling rules. I designed a shared job-queue architecture with per-marketplace backoff strategies to ensure sync reliability without hitting limits.
Data Normalisation Across APIs
Amazon, Walmart, and WooCommerce all return orders and inventory in different formats. I built a normalisation layer that maps marketplace-specific schemas to a unified internal model, making the UI and business logic marketplace-agnostic.
Test Coverage for External APIs
Testing marketplace integrations without making real API calls required VCR cassettes and carefully crafted factory objects to simulate real responses while keeping tests fast and deterministic.
Let's Work Together
I'm currently available for freelance projects and open to new opportunities. If you have an idea or just want to say hi, send me a message!