Strangler Fig Pattern

Status: 🟡 Starter note

Problem

A legacy system needs to evolve without a risky big-bang rewrite.

Core idea

Gradually route capabilities to new implementations while the legacy system continues operating.

Clients
   |
   v
Routing / Facade
   |
   +---- New capability
   |
   +---- Legacy capability

Questions

1. How do you choose the migration boundary?
2. How do you handle shared data?
3. How do you validate parity?
4. When should the legacy system finally be retired?