Two days, built for engineers.

Forensic DDD: Reverse-Engineering the Domain Your Legacy System Never Documented

Raj Navakoti

The DDD textbook promises a clean path: gather the experts, run Event Storming, discover your bounded contexts. Beautiful — and almost never how it goes in a large enterprise. Try it when you've inherited a 30-year-old delivery domain: built by vendors who left years ago, powering millions of daily transactions, its logic scattered across monoliths, legacy databases, and black boxes nobody can see inside. Nobody wrote it down. The people who built it are gone. You run Event Storming, people tell you how they think it works — and the production logs show it doing something else entirely. This talk is about forensic DDD: treating a legacy system like an archaeological dig, using production artifacts — logs, schemas, APIs, incidents, error codes — to reverse-engineer the domain model nobody ever documented. I'll share practical detective techniques for surfacing bounded contexts and hidden business rules from that evidence, how to reconcile the domain people remember with the one actually running (the gap is where the real insight lives), and how to extract safely without a big-bang rewrite. Legacy systems aren't just tech debt — they're dense archives of domain knowledge, if you know how to read them.