How to Move from Monolith to a Service Based Architecture

Migrating from a monolith to microservices requires deliberate patterns rather than a big-bang rewrite. Four key strategies are covered: the Strangler Fig Pattern (incrementally routing traffic to new services via an API gateway), the Parallel Run Pattern (running both systems simultaneously to validate equivalence), the Collaborator Pattern (decorating the monolith with microservices to add features without touching core logic), and Change Data Capture (streaming database changes via tools like Debezium or Kafka Connect to keep microservices in sync). These patterns are designed to work together in sequence to reduce risk and gradually separate concerns.