Senior .NET Developer (LINQ / EF Core Internals / Expression Trees) | Contract | Remote

Senior .NET Developer (LINQ / EF Core Internals / Expression Trees)

Engagement: Contract
Work Mode: Remote

Role Overview

We are seeking a highly senior .NET Developer with deep expertise in LINQ internals, Entity Framework Core query translation, and runtime metaprogramming.

This role requires someone who can design and build core framework-level components including dynamic query engines and fluent APIs not just consume existing libraries or frameworks.

If your experience is limited to using LINQ for CRUD operations, this role is not a fit.

Required Skills (Must-Have)

• Expert-level experience with System.Linq.Expressions

• Hands-on experience building, traversing, and rewriting Expression Trees at runtime using ExpressionVisitor

• Strong understanding of Entity Framework Core internals, including:

  • LINQ-to-SQL translation pipeline

  • Troubleshooting could not be translated errors

  • Refactoring C# logic into SQL-compatible joins and projections

• Experience designing custom LINQ providers or query engines

• Advanced knowledge of IQueryable / IQueryProvider

• Proficiency in runtime type generation, reflection, and metaprogramming

• Experience designing Fluent APIs and Builder patterns (similar to EF Core Fluent API)

Advanced C# & Architecture Skills

• Strong functional programming concepts in C#:

  • Generics

  • Delegates

  • Higher-order functions

• Ability to treat logic as data and build composable, reusable abstractions

• Strong understanding of performance, memory management, and expression caching

• Experience avoiding memory leaks in dynamic runtime systems

Nice-to-Have (Strong Plus)

• Experience with Reflection.Emit, Roslyn, or IL generation

• Experience building SDKs, libraries, or internal frameworks

• Open-source contributions (especially LINQ, EF Core, ORMs)

• Experience in high-performance or data-intensive systems

What We re Looking For

Someone who builds the engine, not just uses it
Comfortable working deep in the .NET runtime and EF Core internals
Thinks like a framework or platform engineer

Experience Level

• 8+ years of hands-on C# / .NET development

• Senior / Principal / Architect-level mindset required

Screening Note

Candidates must demonstrate real-world experience with Expression Trees, EF Core internals, and runtime query rewriting during technical interviews.