Senior .NET Developer

Qualysoft; United States; Hybrid; USD 120,000 - 180,000; Full time

Benefits offered by this job

Premium medical package

Lunch Tickets

Bookster subscription

13th salary

Flexible working program

Remote-friendly environment

Career growth opportunities

Job summary

Qualysoft, a Vienna-based global IT services provider, is seeking an senior backend engineer to design, develop and maintain backend apps using C#, .NET, and ASP.NET Core.

You will translate requirements into robust APIs, integrate with Kafka, and ensure scalable data access via Oracle and SQL. Join an international team delivering enterprise solutions with modern CI/CD, containerization, and AI-assisted development.

Qualifications

• Minimum 7 years of professional software development experience in enterprise environments.
• Minimum 5 years of hands-on backend development with C# and .NET / .NET Core.
• Minimum 3 years of hands-on experience with ASP.NET Core.
• Minimum 3 years designing and implementing REST APIs and system-to-system integrations.
• Minimum 2 years practical experience with relational databases, including Oracle and SQL.
• Minimum 2 years experience with messaging or event-driven solutions, preferably Apache Kafka.
• Minimum 2 years experience with Docker and container orchestration platforms such as Kubernetes or OpenShift.
• Proven experience delivering business-critical enterprise applications through the full software delivery lifecycle.
• Experience in banking, financial services or another highly regulated industry is strongly preferred; minimum 2 years for banking-experienced.

Responsibilities

• Design, develop and maintain backend applications and services using C#, .NET and ASP.NET Core.
• Analyze requirements and translate into maintainable solutions.
• Design and implement REST APIs and system integrations with versioned contracts.
• Develop reusable integration capabilities and avoid point-to-point solutions where possible.
• Implement synchronous, asynchronous and event-driven interaction patterns.
• Integrate applications using Kafka or equivalent messaging platforms.
• Develop and optimize DB interactions with Oracle and SQL.
• Apply architectural patterns including Clean Architecture and DDD.
• Implement authentication and authorization with OAuth2/JWT.
• Build automated unit, component and integration tests (xUnit, NUnit, Moq).
• Participate in code reviews and maintain standards for quality, security and performance.
• Containerize applications and support delivery via Docker and OpenShift/Kubernetes.
• Contribute to CI/CD and build automation (GitHub Actions).
• Implement logging, metrics and tracing per observability standards.
• Identify and resolve scalability and performance issues during development and testing.
• Create and maintain technical docs, API specs and implementation notes.
• Use enterprise AI tools responsibly to boost productivity while validating output.

Skills

C#

.NET

ASP.NET Core

REST APIs

Docker

Kubernetes

OpenShift

Kafka

SQL

Unit testing

Tools

Oracle

GitHub Actions

xUnit

NUnit

Moq

Job description

About Qualysoft

• 25 years of experience in software engineering, established in Vienna, Austria
• Active in Romania since 2007, with office in central Bucharest (Bd. Iancu de Hunedoara 54B)
• Delivering End to End IT Consulting Services - From Team Augmentation and Dedicated Teams to Custom Software Development
• We deliver scalable enterprise systems, intelligent automation frameworks, and digital transformation platforms
• Cross-industry experience by sustaining global players in BSFI (Banking, financial services and insurance), Telecom,Retail & E-commerce, Energy and Utilities, Automotive, Manufacturing, Logitics, High Tech
• Global Presence: Switzerland,Germany,Austria,Sweden,Hungary,Slovakia,Serbia,Romania, and Indonesia
• International team of 500+ software engineers
• Strategic partnerships: Microsoft Cloud Certified Partner, Tricentis Solutions Partner in Test Automation and Test Management, Creatio Exclusive Partner, Doxee Implementation Partner
• Powered by cutting-edge technologies: AI, Data & Analytics, Cloud, DevOps, IoT, and Test Automation.
• Project beneficiaries ranging from large-scale enterprises to startups
• Stable growth and revenue increase year over year, a resilient organisation in volatile IT market conditions
• Quality-first mindset, culture of innovation, and long-term client partnerships
• Global and local reach – trusted by key industry players in Europe and the US

Responsibilities

• Design, develop and maintain backend applications and services using C#, .NET and ASP.NET Core.
• Analyze business and technical requirements and translate them into clear, maintainable and testable solutions.
• Design and implement REST APIs and system-to-system integrations with clear, versioned contracts.
• Contribute to reusable integration capabilities and avoid application-specific point-to-point solutions where a generic service is appropriate.
• Design and implement synchronous, asynchronous and event-driven interaction patterns based on solution needs.
• Integrate applications using Apache Kafka or equivalent enterprise messaging platforms.
• Develop and optimize database interactions with Oracle and other relational databases, including SQL performance considerations.
• Apply appropriate architectural patterns, including Clean Architecture, Domain-Driven Design and event-driven architecture.
• Implement authentication and authorization mechanisms using OAuth 2.0, JWT and enterprise access-management solutions.
• Build automated unit, component and integration tests using xUnit, NUnit, Moq or equivalent frameworks.
• Participate in code reviews and contribute to clean code, security, performance and engineering-quality standards.
• Containerize applications and support delivery through Docker and OpenShift/Kubernetes-based platforms.
• Contribute to CI/CD and build automation using GitHub Actions or equivalent tooling.
• Implement logging, metrics and distributed tracing aligned with the organization’s observability standards.
• Identify and resolve scalability, reliability and performance issues during development and testing.
• Create and maintain technical documentation, API specifications and implementation notes.
• Use enterprise-approved generative AI tools responsibly to improve development, testing and documentation productivity, while validating all generated output.

Qualifications

• Minimum 7 years of professional software development experience in enterprise environments.
• Minimum 5 years of hands-on backend development experience with C# and .NET / .NET Core.
• Minimum 3 years of hands-on experience with ASP.NET Core.
• Minimum 3 years of experience designing and implementing REST APIs and system-to-system integrations.
• Minimum 2 years of practical experience with relational databases, including Oracle and SQL.
• Minimum 2 years of experience with messaging or event-driven solutions, preferably Apache Kafka.
• Minimum 2 years of experience with Docker and container orchestration platforms such as Kubernetes or OpenShift.
• Proven experience delivering business-critical enterprise applications through the full software delivery lifecycle.
• Experience in banking, financial services or another highly regulated industry is strongly preferred; minimum 2 years is preferred for candidates presented as banking-experienced.

What We Offer

• 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 (we value ownership, autonomy, and healthy work-life balance) 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

*We are an equal opportunity employer and value diversity. All employment decisions are made without regard to age, gender, disability, race, ethnicity, religion, sexual orientation, or any other protected characteristic. We encourage applicants from all backgrounds to apply.*