What is Strangler Fig Pattern?
Turkish: Strangler Fig Deseni
The Strangler Fig pattern replaces parts of an old monolith with new services step by step, spreading modernization risk.
What is the Strangler Fig Pattern?
The Strangler Fig pattern is a modernization approach that replaces parts of a working legacy system gradually instead of rewriting everything at once. The name comes from a fig that grows around a tree and eventually takes its place: the old system is not shut down immediately; traffic moves to new parts as they become ready.
In practice, a routing layer, API gateway, or proxy is placed in front of the old monolith. When one business capability is moved to a new service, traffic for that route goes to the new application; unmoved areas remain in the old system. Modules such as billing, users, inventory, or reporting can be separated one by one.
When It Fits
This pattern is useful for organizations with critical business processes that cannot tolerate a long outage. Compared with a big-bang rewrite, it allows learning from the live system and rolling back smaller steps. Although it is often discussed with microservice migrations, the target does not have to be microservices; a modular monolith or separate application may also be appropriate.
The hard parts are data ownership, synchronization between old and new systems, temporary integration cost, and deciding when old code can finally be removed. A successful migration defines product boundaries and operational ownership as clearly as the technical routing plan.