Legacy Monolith Replacement at Scale

The Challenge & Solution

A multi-tenant e-commerce marketplace platform serving 400+ tenants needed to replace its legacy .NET Framework 4.8 repricing monolith, which was consuming $38,000/month in infrastructure, executing 93.5M unnecessary SQL queries daily, and processing 45B individual UPDATE statements. Ekolabs was engaged as Fractional CTO, providing hands-on technical leadership across architecture, infrastructure, and vendor management. The new engine was built in NestJS/TypeScript across 6 phases using AI-assisted development (Claude Code agents), delivered with 597 tests at 94.73% coverage. Infrastructure costs dropped to $811/month. An offshore development contract was restructured to produce $500K in annual savings.