Senior .NET Backend Engineer — Remote/Madrid, Robust APIs

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

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