Legacy Application Modernization: From WinForms to Blazor in Weeks

Cost varies based on codebase size, complexity, target stack, and the approach you choose. For a mid-market enterprise application, a manual rewrite typically runs $800K–$1.2M. Generic AI tooling can reduce this to $500K–$900K, though inconsistent output quality often drives up rework costs.

VELO's purpose-built approach delivers the same outcome for $320K–$480K — roughly 40–60% less than a traditional rewrite — because AI handles the high-volume transformation work that would otherwise require large teams of senior developers. Fixed pricing also eliminates the scope creep risk common in T&M engagements.

A rewrite starts from scratch — developers build a new application using the old one as a reference, discarding the original code entirely. This gives maximum architectural freedom but carries the highest cost, schedule risk, and chance of missing undocumented business logic.

Legacy modernization preserves the existing business logic and data while migrating it to a modern platform, language, and infrastructure. It's re-implementation, not reimagination — and it's where AI-assisted approaches like VELO deliver the most value. Because the transformation follows known patterns (converting WinForms to Blazor components, for example), purpose-built agents can handle the bulk of the work with deterministic validation, leaving engineers to focus on architecture, testing, and the judgment calls that AI cannot make.