How to connect marketplaces to your inventory system

A retail distributor sold on three marketplaces and one online store. Stock was updated manually in each place, so sold-out items could still be ordered.

The problem

The warehouse team copied stock numbers from one spreadsheet into four different dashboards every morning and evening. A few hours of difference was enough to oversell.

Our approach

• One source of truth: stock lives in the central system, not in the marketplaces
• Stock changes are sent through webhooks, with a queue and retries when delivery fails
• Every order is recorded with a unique ID so it cannot be processed twice

What we learned

Each marketplace has different API rate limits, and the documentation does not always match real behavior. We added logs that the operations team can read, not just developers, so problems can be traced without waiting for us.

The result

Twelve integrations run at 99.9% uptime, and stock syncs in under a minute.