Modernizing legacy applications doesn’t have to be a multi-year rewrite. A pragmatic approach combines automated code conversion with targeted refactoring and comprehensive testing. Begin by mapping dependencies and defining parity criteria: inputs, outputs, and performance envelopes that new code must meet. Utilize AST-based transpilers and pattern libraries to convert idioms (such as loops, I/O, and date math) into modern equivalents, then layer linters and formatters to enhance readability. Auto-generate unit and “golden” regression tests from production traces to ensure behavior stays identical. Where the old stack relies on global state or procedural data access, encapsulate side effects behind adapters so you can adopt modern frameworks incrementally. Run converted modules in CI/CD with static analysis, SAST/DAST, and profiling; tune hot paths before switching traffic. The result: quicker migration, lower risk, and maintainable code that unlocks cloud, security, and hiring benefits.