legacy-modernization

name	legacy-modernization
description	Modernize legacy systems without rewriting from scratch. Use strangler fig, facade, and strategic refactoring.

Legacy Modernization

Modernize legacy systems incrementally using strangler fig pattern, facade layers, and strategic refactoring.

Instructions

1. Assessment: Understand current system behavior, pain points
2. Strangler Fig: New services alongside old monolith; gradually redirect traffic
3. Facade Layer: Wrap legacy with modern API without changing internals
4. Refactoring: Extract modules one at a time to modern stack
5. Incremental Value: Each phase delivers business value

Anti-Patterns

• Rewrite Everything: "Let's rebuild it right." Result: 2-3 years, misses market. Guard: Keep old system running while new builds alongside.
• No Business Alignment: Modernize things users don't care about. Guard: Modernize parts causing business pain first.

Further Reading

• Monolith to Microservices — specific modernization patterns