DE Shaw·Software Engineer·Technical Phone Screen
May 2026
Interviewed at DE Shaw for a .NET backend role and spent most of my prep time on DSA because that's all the recruiter hinted at, only to walk into a legacy .NET Framework debugging session instead. The communication breakdown before and after was genuinely worse than the rejection itself.
- Debug a legacy .NET Framework 4.x C# codebase and walk through your fix.
- Explain dependency injection and how you'd apply it in a .NET application.
- When and why would you use ConcurrentDictionary versus a regular dictionary with a lock?
- How does IDisposable work and when should you implement it?
- What is IQueryable and how does it differ from IEnumerable in a backend context?
- Walk through your approach to backend architecture and concurrency for a given system.
“Walked in expecting DSA and got handed old framework code with syntax errors in it.”