Strangler Fig: Incremental Migration

Migrating a monolith means changing a live system without users noticing.

A big-bang rewrite is risky because the old system keeps changing, and the new one often misses years of hidden behavior and edge cases.

The strangler fig pattern reduces that risk. You build new services around the monolith, route small pieces of traffic to them, and slowly shrink the monolith until there is nothing left to serve.

This chapter covers incremental routing, safe cutovers, and retiring the monolith without a risky rewrite.