Senior .Net Engineer

Qualysoft

. Design, develop, test, and maintain backend services and REST APIs using .NET, C#, and ASP.NET Core .

Posted 10/20/2026full-timeBucharest • RomaniaSeniorWebsite

Core Competencies

Role fit

Core Competencies

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Demonstrates extensive experience in backend development using C#, .NET, and ASP.NET Core, with a strong focus on secure coding practices, REST API design, and database management using Microsoft SQL Server. Proven ability to mentor developers and collaborate effectively across teams to enhance code quality and system performance.

Highest-signal resume keywords

C#.NET / .NET CoreASP.NET CoreMicrosoft SQL ServerREST API Design

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Hard Skills

T-SQLEntity Framework CoreDapperAsynchronous ProgrammingObject-Oriented ProgrammingSOLID PrinciplesDesign PatternsUnit TestingCI/CD PipelinesWeb Application Security

Soft Skills

CommunicationCollaborationMentoring

Tools & Technologies

GitHub CopilotRabbitMQGitAzure DevOps

Industry Keywords

Backend ServicesREST APIsMulti-TenancyCode ReviewsPerformance Optimization

Tech Stack

Tools & technologies

ASP.NETAzureEntity FrameworkMS SQL ServerRabbitMQSQL.NET

About the role

Key responsibilities & impact

Design, develop, test, and maintain backend services and REST APIs using .NET, C#, and ASP.NET Core
Contribute to backend architecture decisions with a focus on maintainability, security, and multi-tenancy
Write efficient T-SQL queries and stored procedures in Microsoft SQL Server and improve query performance through appropriate indexing, in collaboration with the DBA team
Implement data access using Entity Framework Core and/or Dapper
Implement integrations with internal and external systems, including message-based communication such as RabbitMQ
Implement secure backend practices, including authentication, authorization, and role-based access
Troubleshoot and resolve defects, performance issues, and production incidents
Write and maintain unit and integration tests
Lead code reviews and contribute to backend coding standards and best practices
Participate in modernization and refactoring of existing services
Use GitHub Copilot and other approved AI-assisted development tools to improve productivity while ensuring code quality and correctness
Mentor mid-level and junior developers and collaborate with Product, QA, DBA, and DevOps teams

Requirements

What you’ll need

At least 7 years of professional experience with C#, .NET / .NET Core, and ASP.NET Core
Relevant hands-on experience with Microsoft SQL Server as a relational database
Ability to write complex T-SQL queries, including the use of CTEs and temporary tables
Knowledge of indexing strategies and the ability to read an execution plan to identify slow queries
Experience with Entity Framework Core and/or Dapper
Experience designing and consuming REST APIs
Experience with asynchronous programming and message-based integrations (e.g. RabbitMQ)
Good knowledge of object-oriented programming, SOLID principles, design patterns, and clean code
Good understanding of web application security, authentication, authorization, and role-based access
Practical experience using GitHub Copilot or similar AI-assisted development tools, while maintaining responsibility for code quality and correctness
Experience with Git, code reviews, unit testing, and CI/CD pipelines (Azure DevOps preferred)
Good communication, collaboration, and mentoring skills

Benefits

Comp & perks

Premium medical package
Lunch Tickets & Pluxee Card
Bookster subscription
13th salary/yearly bonuses
Enterprise job security with a startup mentality (diverse & engaging environment, international exposure, flat hierarchy) under the stability of a secure multinational
A supportive culture with great colleagues, team events and activities
Flexible working program and openness to remote work
Collaborative mindset – employees shape their own benefits, tools, team events and internal practices
Diverse opportunities in Software Development with international exposure
Flexibility to choose projects aligned with your career path and technical goals
Access to leading learning platforms, courses, and certifications (Pluralsight, Udemy, Microsoft, Google Cloud)
Career growth & learning – mentorship programs, certifications, professional development opportunities, and above-market salary