What is the Strangler Fig pattern?

The Strangler Fig pattern is an approach to gradually replacing or modernizing an outdated system.

The idea is not to rewrite the entire system at once, but to gradually create new functionality around the old one, slowly "wrapping" and displacing it. The new system intercepts some functions, while the old one continues to operate where the new one has not yet been implemented.

This approach reduces risks, allows for smooth migration without interrupting user operations, and simplifies testing and deployment of new components.

Example: when transitioning from a monolithic application to microservices, individual services can be gradually isolated, directing requests to them, while the monolith remains only with minimal functionality.