Forensic DDD: Reverse-Engineering Domains from Legacy Systems That Won't Talk

You've been handed a legacy system. A 10-year-old monolith — partially decomposed, partially understood, fully in production. The original vendor is gone. The documentation is three years stale.

This article presents eight forensic techniques for discovering real domain boundaries: API Contract Archaeology, Schema Archaeology, Database Access Patterns, Temporal Coupling Detection, Event Stream Forensics, Slack History Mining, Team Boundary Mapping, and a Stakeholder Interview Protocol.

Event Storming tells you what people think the system does. Production tells you what it actually does.

Originally published on Medium.