Ingeniero Senior .NET

Ruideria; Madrid; Hybrid; EUR 70,000 - 100,000; Full time

Job summary

Ruideria is seeking a Senior .NET Backend Developer to drive backend architecture for the flagship product and deliver robust RESTful APIs. You will collaborate with Frontend and UX/UI teams to ensure scalability, performance, and reliability of the server-side platform.

The role requires 3+ years in backend development, strong C#/.NET expertise, and experience with API design and testing. The position offers 50% remote work and 50% in Madrid, with a focus on secure data handling and

Qualifications

• 3+ years of backend development experience.
• 1+ year with Claude Code and/or OpenCode.
• 50% remote, 50% in Madrid.
• Strong proficiency in C# and the .NET ecosystem (ASP.NET Core, DI, middleware).
• Experience with API design, versioning, and documentation (OpenAPI/Swagger).
• Experience with data access patterns and libraries (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.

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.

Tools

C#

.NET Core

ASP.NET Core

Entity Framework Core

Dapper

OpenAPI/Swagger

SQL

NoSQL

CI/CD

Job 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