I built a .NET legacy migration tool that actually migrates your code — not just tells you what to do. Roast it.
For the past few months I've been building NexShift, a tool that analyzes and migrates .NET Framework 4.x repos to .NET 8/9.
I know what you're thinking — "just use .NET Upgrade Assistant". I tried. It gives you a report. That's it. NexShift actually does the work.
What it does:
- Analyzes your repo (GitHub URL) and gives you a migration score with a breakdown of exactly what's blocking you
- Detects deprecated NuGet packages and suggests modern replacements
- Automatically converts .csproj to SDK-style format
- Migrates Web.config → appsettings.json
- Migrates Global.asax → Program.cs
- Uses Claude AI only when deterministic rules aren't enough (HttpContext.Current → IHttpContextAccessor, OWIN middleware → ASP.NET Core, etc.)
- Generates a prioritized Migration Backlog with three categories: ✅ Automated, ⚠️ Needs review, ❌ Manual decision required
- Outputs a ZIP with all migrated files + a PDF report
- Never touches business logic — only migrates infrastructure
The honest limitations:
- Web Forms UI can't be migrated automatically (nobody can do that)
- Full WCF server migration is out of scope for now
- Business logic mixed with infrastructure gets flagged for manual review, not auto-migrated
What I want to know:
Would you actually use this on a real legacy project?
What's the one thing that would make you pay for it?
Is there something that already does this that I'm missing?
I've tested it on several legacy repos internally. Haven't launched publicly yet. Trying to figure out if this solves a real pain or if I'm just solving my own problem.
Happy to answer technical questions about how the migration engine works.