strangler-fig

Migrate from a monolith to microservices without downtime by using the Strangler Fig pattern to incrementally route new behavior through a facade, moving one capability at a time while keeping the legacy system running. This ensures continuous delivery and safe rollbacks.

The Strangler Fig pattern is an incremental migration strategy that gradually replaces a legacy monolith by intercepting requests through a routing facade. It routes new capabilities to a modern architecture while delegating remaining functionality to the legacy system until migration is complete.

Choose incremental migration over a big-bang rewrite when your legacy monolith is too risky or complex to replace at once. If system capabilities are reasonably decomposable and a routing layer can be introduced without significant latency, gradual replacement minimizes risk.

Yes, you can roll back a microservices migration safely because the Strangler Fig pattern maintains a working, releasable system at every step. The routing facade allows you to revert traffic back to the legacy monolith if a newly migrated capability encounters issues.

The primary limitation of using a facade for monolith decomposition is that your system capabilities must be reasonably decomposable. Additionally, introducing a routing layer must not add significant latency to request paths, which can constrain highly coupled legacy systems.