Senior Backend API Engineer - .NET & Cloud

AdvanceWorks; Portugal; On-site; EUR 42,000 - 64,000; Full time

Benefits offered by this job

International team

Formal training and certifications

Challenging projects with modern tech

Flexible hours and autonomy

Job summary

AdvanceWorks is seeking an experienced Backend .NET Developer to design, build and evolve secure APIs for a Nordic healthcare client. You will work in a cross-disciplinary team on cloud-native services, ensuring robust security, compliance and code quality.

The role emphasizes API-first development, maintainable architectures, and ownership of meaningful parts of a regulated, high-impact system. Fluency in English and a passion for learning are essential.

Qualifications

• 3+ years with .NET 5+ and .NET 8+ in the last 3 years.
• Proven ability to write SQL by hand in backend code.
• Experience with automated unit/integration tests (xUnit/NUnit).
• Experience designing long-lasting API systems (REST, JSON, OpenAPI, auto code generation).
• Experience with access control and MFA.
• CI/CD, IaC and automated quality gates.
• Security-by-design and OWASP Top 10/CWE.
• Knowledge of GDPR.

Responsibilities

• Design, develop and maintain backend services and REST APIs in .NET 8+ and ASP.NET, following an API-first approach.
• Structure API systems using FastEndpoints / REPR or MVC for maintainability and scalability.
• Write and optimize SQL queries and database logic by hand (Dapper/ADO.NET).
• Build and maintain automated unit and integration tests (xUnit/NUnit).
• Implement claims-based access control and MFA, and make sensitive data actions traceable.
• Apply security-by-design and defend against OWASP Top 10/CWE vulnerabilities.
• Contribute to CI/CD pipelines, IaC and automated quality gates; ensure code quality with SonarCloud.
• Build cloud-native services for Kubernetes with resilience patterns and proper secrets management.
• Take ownership of work packages and act as point of contact with stakeholders.
• Collaborate with cross-functional teams to support digital transformation.
• Contribute to responsible AI usage when building software handling personal data.

Skills

.NET

SQL

Unit tests

API design

Security

CI/CD

GDPR

English

Collaboration

Learning

Tools

xUnit

NUnit

OpenAPI

Dapper

ADO.NET

Kubernetes

Job description

AdvanceWorks is seeking an experienced Backend .NET Developer to design, build and evolve secure APIs for a Nordic healthcare client. You will work in a cross-disciplinary team on cloud-native services, ensuring robust security, compliance and code quality.

The role emphasizes API-first development, maintainable architectures, and ownership of meaningful parts of a regulated, high-impact system. Fluency in English and a passion for learning are essential.