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 Open Code 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 (Open API/Swagger) Experience with data access patterns and libraries (e.g., Entity Framework Core, Dapper) Knowledge of SQL and/or No SQL databases and performance tuning Experience with testing practices (unit/integration tests) and CI/CD workflows #J-18808-Ljbffr

📌 Ingeniero senior .net (Madrid)
🏢 RuiderIA
📍 Madrid