Legacy Rebirth

The Case: An insurance company with a 15-year-old ASP.NET WebForms application that is impossible to maintain and won't run in modern browsers.

1. Step 1: The 'Side-by-Side' Strategy

We didn't try to rewrite the whole app. We created a new **Blazor Server** project and hosted it under a sub-path (e.g., /modern). We shared the Authentication Cookie between the old WebForms app and the new Blazor app, so the user could switch between them without logging in again.

2. Step 2: Componentization

We identified the most 'painful' pages in WebForms and rebuilt them as Blazor components. Because both use C#, we were able to copy-paste much of the business logic and data access code with only minor adjustments. We used a **Razor Class Library** to hold these new components so they could be reused in both the interim 'Side-by-Side' app and the final full Blazor app.

3. The Final Result

After 12 months, the entire app was migrated. The page size dropped by 70%, the server load dropped by 50%, and the developers are now building features 3x faster using modern C# 12 and .NET 8 features. The 'Legacy' tag is finally gone.

3. Architect Insight

Q: "Why choose Blazor over React for this migration?"

Architect Answer: "Lower risk. The team already knew C#. Rewriting in React would have required hiring new people or retraining everyone in JS/TypeScript/React. With Blazor, they were productive in week one. Architecture is always about balancing technical perfection with business reality and team skills."