Keeping Inventory in Sync Across Amazon and eBay in Real Time

Sellers running multi-channel e-commerce face a constant risk: sell the same unit on two platforms before either system knows it's gone. For Packit, I built the infrastructure to make sure that never happens.

How it works:

Connects a seller's Amazon and eBay accounts through the Amazon SP-API and eBay API

Keeps inventory, orders, shipping, and channel data synced in real time across both platforms

No manual reconciliation, no overselling, no guessing which channel has accurate stock counts

The operator-facing surface I built:

An order dispatch queue that automatically segments orders into unprocessed, unshipped, cancelled, and pending — so operations teams know exactly what needs attention without digging through a flat order list

A cross-channel analytics dashboard tracking revenue, units sold, average order value, and return rate — giving sellers one view instead of switching between Amazon Seller Central and eBay's dashboard

Inventory health monitoring with low-stock alerts, so restocking happens before a listing goes dark

The engineering challenge: background sync that doesn't block anything

Marketplace APIs are slow and rate-limited. If sync ran in the request cycle, the interface would grind to a halt every time inventory updated. Instead, I built the sync to run on Sidekiq in the background — so orders, stock levels, and shipping data update continuously without ever blocking what the user is doing in the app.

Why this matters for the kind of work I take on

This is the pattern I keep coming back to: connect multiple external systems, keep data consistent between them, and make sure background processing doesn't compromise the user-facing experience. If you're running a multi-channel operation and your systems don't talk to each other cleanly, that's exactly the kind of problem I solve.