Overview
Architecture for a phased migration from a legacy application and database estate to a cloud platform.
Problem
A domain-heavy legacy stack cannot cut over in one step. Data and writes have to move without stopping the business.
My Role
Architecture and modernization design: target-cloud and data model, domain boundaries, and the coexistence patterns needed to move writes safely.
What I Built
- Target-cloud and data design.
- Domain boundaries and coexistence of legacy and new systems.
- Shadow mode, transition bridge, outbox and dead-letter handling.
Architecture & decisions
Strangler-style coexistence rather than a single big-bang rewrite. Java, PostgreSQL and cloud delivery, with domain-oriented data boundaries.
Technologies
- Java
- PostgreSQL
- AWS
Outcome
Migration architecture and integration patterns are defined.
Case boundary
Internal programme and client names are omitted. The case focuses on migration architecture.