AWS re:Invent 2025 - Vibe modernize your .NET applications using AWS Transform and Kiro (MAM343)
Source: Dev.to
Overview
AWS re:Invent 2025 – Vibe modernize your .NET applications using AWS Transform and Kiro (MAM343)
In this session Alex and Prasad demonstrate modernizing a legacy .NET Framework application called Contoso University through seven steps using AWS Transform for .NET and Kiro. The migration includes:
- Porting from .NET Framework 4.8 to .NET 8
- Fixing compilation errors
- Replacing SQL Server with Aurora PostgreSQL
- Migrating MSMQ to Amazon SQS
- Extracting a notification microservice from the monolith
- Refactoring Razor Views to a React frontend
- Deploying everything on AWS with CDK
The final architecture runs on Amazon EC2 Linux instances with Aurora PostgreSQL, CloudFront, and SQS, turning a Windows‑dependent monolith into a cloud‑native microservices application.
Introduction: Modernizing Legacy .NET Framework Applications with Agentic AI
Good afternoon! In this code‑talk we’ll show how to modernize legacy .NET Framework applications using agentic AI tools AWS Transform for .NET and Kiro. The session is heavy on live coding.
How many of you are still managing legacy .NET Framework applications?
Almost everyone—perfect, you’re in the right place.
Legacy .NET Modernization Pillars
- Code Modernization – Move from .NET Framework (Windows‑only) to the latest LTS version of .NET (e.g., .NET 8).
- Architecture Modernization – Shift from monoliths to microservices and event‑driven patterns.
- Infrastructure Modernization – Run on Linux (EC2, containers, or serverless) instead of Windows/IIS.
Understanding the Contoso University Application
Contoso University is an open‑source ASP.NET MVC application that simulates a university management system (student enrollment, course management, instructor assignment). It relies heavily on Windows‑specific components:
- Queues: MSMQ
- Database: SQL Server (via Entity Framework)
- Presentation: Razor Views with MVC controllers
The codebase lives in a GitHub repository and targets .NET Framework 4.8 with a large web.config file, multiple controllers, and a classic Entity Framework data layer.
Seven‑Step Modernization Plan
| Step | Description |
|---|---|
| 1. Port to .NET 8 | Use AWS Transform for .NET to convert the project files and update APIs. |
| 2. Resolve Compile Errors | Leverage Kiro to automatically generate fixes and refactor code. |
| 3. Replace SQL Server | Migrate the data layer to Amazon Aurora PostgreSQL (EF Core provider). |
| 4. Swap MSMQ → SQS | Replace Windows‑only MSMQ with Amazon SQS for reliable messaging. |
| 5. Extract Notification Service | Pull the notification logic into an independent microservice. |
| 6. Front‑end Refactor | Convert Razor Views to a React SPA, communicating via REST/GraphQL. |
| 7. Deploy with CDK | Define the full infrastructure (EC2 Linux, Aurora, SQS, CloudFront) using AWS CDK. |
Tooling Overview
AWS Transform for .NET
- Automated migration from .NET Framework to .NET 8/10.
- Updates project files, NuGet packages, and suggests code changes.
Kiro
- AI‑driven spec‑driven development platform.
- Generates requirements, design docs, and implementation tasks from code.
- Fixes compile‑time errors and assists with refactoring.
Final Architecture
- Compute: Amazon EC2 (Linux) instances running the .NET 8 application.
- Database: Amazon Aurora PostgreSQL.
- Messaging: Amazon SQS for asynchronous communication.
- Frontend: React SPA delivered via Amazon CloudFront.
- Infrastructure as Code: AWS CDK stacks for reproducible deployments.
This transformation turns a Windows‑bound monolith into a scalable, cloud‑native microservices solution.