A Single Source of Truth for All Warehouse Transactions

Wayfair partnered with 7Span to eliminate siloed financial data and build a centralized ledgering system for warehouse transactions. By integrating 3P WMS streams, modernizing legacy data flows, and scaling real-time processing, we enabled finance teams to track costs, reconcile inventory, and operate with complete confidence in their data.

industry

E-commerce & Retail

Services

Backend Engineering, Data Migration, Stream Processing, System Modernization

Introduction

Wayfair’s finance operations relied on fragmented, outdated WMS tables spread across fulfillment centers. These legacy systems were slow, interconnected, and nearing deprecation creating risk for critical processes like cost tracking, financial analysis, and inventory reconciliation.

The finance team needed a new, unified source of truth that:

No longer relied on direct access to fulfillment/WMS databases
Standardized inbound data from 3rd-party warehouse systems
Supported real-time increments and decrements to inventory
Provided accurate cost and ledgering visibility
Scaled with exponential data growth

The goal: decouple finance from operational systems and build a centralized ledger they can trust.

The Challenge

This wasn’t a simple build—massive operational complexities had to be resolved:

Legacy WMS tables contained huge volumes of historical data
Real-time migration slowed drastically as data grew
Kafka scaling didn’t fully solve throughput bottlenecks
A hidden DB trigger was inserting records into another table without proper indexing
Finance operations depended on fast, correct ledger data (delays = financial blockers)