Role Description
As a Senior .NET Backend Developer, you will drive architectural decisions for our flagship product’s server-side platform. You will work closely with Frontend and UX/UI teams to design and deliver robust APIs, ensure scalability, and maintain high performance and reliability. Freelance or permanent.

Responsibilities
Design, develop, and maintain backend services and RESTful APIs using .NET Core
Drive backend architecture decisions (modularity, scalability, reliability, observability)
Build reusable backend components, shared libraries, and utilities for future use
Translate product requirements into clean, maintainable, and well-tested code
Optimize services for performance, throughput, and low latency under high load
Ensure secure data handling, authentication/authorization, and best practices
Implement logging, metrics,



and tracing using Azure-friendly observability tooling
Collaborate with database and platform teams to design efficient data models and integrations
Requirements
3+ years of experience in backend development
1+years of experience with Claude Code and/or OpenCode
50% remote, 50% in Madrid
Strong proficiency in C# and the .NET ecosystem (ASP.NET Core, DI, middleware)
Solid understanding of API design, versioning, and documentation (OpenAPI/Swagger)
Experience with data access patterns and libraries (e.g., Entity Framework Core, Dapper)
Knowledge of SQL and/or NoSQL databases and performance tuning
Experience with testing practices (unit/integration tests) and CI/CD workflows

Envía tu CV a [email protected]

📌 Ingeniero Senior .NET (Madrid)
🏢 RuiderIA
📍 Madrid