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·6 min readLegacyArquitectura

Modernizing a legacy system without stopping the business

A full rewrite is rarely the answer. The strangler fig pattern and incremental migration reduce risk and cost.

Many businesses run on 10- or 15-year-old systems. They work, but every change is slow, expensive and risky. The temptation is to rewrite everything — and it usually goes badly.

Incremental migration

With the strangler fig pattern, new features are built outside the old system and gradually replace its parts. The business never stops.

  • Technical audit to map risks and dependencies.
  • Characterization tests before touching anything.
  • Extract modules ordered by value and risk.
  • CI/CD and observability from the first module.

When a rewrite does make sense

When the system is small, the technology is no longer supported, or the business model changed completely. Even then, we do it in phases.