I was at TDC 2025 to talk about modernizing legacy systems with the Strangler Fig pattern.
Strangling the dragon: modernizing legacy systems with the Strangler Fig pattern
- Mon Oct 20 2025 14:00–14:50 Cosmos 3CD
Stuck in a legacy system that needs modernizing? Feel like the best course of action is to throw it in a dumpster, light it on fire and rewrite everything from scratch —maybe even in a different language?
Hold that thought. While it may be tempting to start a rewrite, rewrites of complicated systems rarely succeed for multiple reasons. Chief among them is time and the fact that not everything can stop and wait for the rewrite, but another important contributor is the second system effect, which usually causes rewrites to be of lesser quality than that which they replace.
In this talk, I’ll share my experiences with the Strangler Fig pattern, a better approach where the original system is gradually replaced by breaking out or rewriting parts into separate systems. I’ll also talk about combining this with Domain Driven Design and how to use the new design to execute an Inverse Conway Manoeuvre to ensure you’re working with Conway’s law and not against it.