Monolith to Microservice Migration
Problem
A legacy Java J2EE monolith running on IBM WebSphere had tightly coupled deployments and long release cycles (~41 days). A single backend change required coordination across multiple teams and extensive regression testing.
Approach
I incrementally extracted a Spring Boot service from the monolith, migrating one endpoint at a time. The existing frontend was reused to validate behavior in test environments, avoiding a risky big-bang rewrite.
Key Decisions
- Chose Cloud SQL over globally distributed databases due to non-global scale requirements and the need for operational simplicity
- Prioritized deployment isolation and rollback safety over premature scalability
- Containerized the service early to stabilize environments and reduce config drift
Outcome
Releases moved to sprint-level cadence, operational risk was reduced, and clear ownership boundaries were established for the extracted service.