Principal Software Engineer
First seen by Alion on Sep 8, 2026.
Job Summary :
We are looking for an experienced Full Stack .NET Developer with strong hands-on expertise in .NET/.NET Core, React.js, and Playwright. The candidate will be responsible for designing, developing, testing, debugging, and maintaining scalable web applications and APIs.
Key Responsibilities :
.NET / Backend Development :
- Design, develop, and maintain enterprise applications using C# and .NET/.NET Core.
- Develop scalable and secure ASP.NET Core Web APIs and RESTful services.
- Implement business logic, validation, exception handling, logging, and authentication/authorization.
- Work with Entity Framework Core, LINQ, dependency injection, middleware, and asynchronous programming.
- Design reusable, maintainable, and testable backend components.
- Optimize application performance, scalability, and reliability.
- Troubleshoot production issues and perform root-cause analysis.
- Integrate applications with internal and external systems through REST APIs and other integration mechanisms.
- Apply clean coding practices and appropriate design patterns.
React Front-End Development :
- Develop responsive and user-friendly web applications using React.js.
- Build reusable React components and modular front-end architecture.
- Work with JavaScript/TypeScript, HTML5, CSS3, and modern React concepts.
- Implement state management, routing, form validation, API integration, and error handling.
- Integrate React applications with .NET REST APIs.
- Optimize front-end performance and application responsiveness.
- Ensure cross-browser compatibility and responsive behavior.
- Participate in UI development, code reviews, debugging, and performance improvements.
Playwright / Test Automation :
- Develop and maintain automated UI and end-to-end test frameworks using Playwright.
- Create reliable automated test cases covering critical application workflows.
- Automate functional, regression, integration, and smoke testing.
- Write Playwright tests using JavaScript/TypeScript.
- Implement reusable test utilities, fixtures, page objects, and test data.
- Execute tests across multiple browsers and environments.
- Analyze test failures, identify defects, and work with developers to resolve issues.
- Integrate Playwright automation into CI/CD pipelines.
- Maintain test scripts as application functionality evolves.
- Improve automation coverage and reduce manual regression-testing effort.
API & Integration :
- Design and consume RESTful APIs.
- Work with JSON, HTTP/HTTPS, authentication, authorization, and API error handling.
- Perform API testing and integration validation.
- Integrate front-end applications with backend services.
- Work with third-party APIs and enterprise integrations.
- Understand API versioning, security, performance, and scalability considerations.
Database Skills :
- Work with relational databases such as SQL Server.
- Write complex SQL queries, joins, stored procedures, functions, and views.
- Perform database design, data validation, and query optimization.
- Work with Entity Framework Core/ORM technologies.
- Troubleshoot database-related application issues and performance bottlenecks.
Software Engineering Practices :
- Follow SOLID principles, clean code, object-oriented programming, and design patterns.
- Participate in Agile/Scrum ceremonies including sprint planning, daily stand-ups, backlog refinement, demos, and retrospectives.
- Perform peer code reviews and maintain coding standards.
- Write unit, integration, and end-to-end tests.
- Participate in technical design and architecture discussions.
- Create technical documentation and maintain application documentation.
CI/CD & DevOps Exposure :
- Work with CI/CD pipelines for application build, testing, and deployment.
- Integrate Playwright automated testing into deployment pipelines.
- Work with tools such as Git, Azure DevOps/GitHub, Jenkins, or similar CI/CD platforms.
- Understand build management, version control, branching strategies, and release processes.
- Troubleshoot build and deployment failures.
- Exposure to Docker and cloud platforms such as Azure or AWS is an advantage.
Security :
- Implement secure coding practices across frontend and backend applications.
- Work with authentication and authorization mechanisms such as JWT, OAuth 2.0, and role-based access control.
- Understand common web application vulnerabilities such as OWASP Top 10.
- Ensure secure handling of user input, APIs, credentials, and sensitive information.
Required Technical Skills :
Backend :
- C#, .NET / .NET Core, ASP.NET Core, Web API / REST API, Entity Framework Core, LINQ, Dependency Injection, Async/Await, Object-Oriented Programming, Design Patterns.
Frontend :
- React.js, JavaScript / TypeScript, HTML5, CSS3, React Hooks, REST API Integration, Responsive Web Development.
Automation :
- Playwright, End-to-End Testing, UI Automation, Regression Testing, Cross-Browser Testing, Page Object Model, Test Fixtures, CI/CD Test Integration.
Database :
- SQL Server, SQL, Stored Procedures, Query Optimization, Entity Framework.
Tools :
- Git, Azure DevOps / GitHub, Postman, Visual Studio / VS Code, CI/CD tools.
Preferred Skills :
- Azure or AWS, Docker, Microservices architecture, TypeScript, Redis or caching technologies, Messaging technologies, Kubernetes, Automated API testing, Performance testing, Agile/Scrum methodology.
Soft Skills :
- Strong analytical and problem-solving skills.
- Excellent verbal and written communication.
- Strong collaboration and stakeholder-management skills.
- Ability to understand business requirements and convert them into technical solutions.
- Strong debugging and troubleshooting capability.
- Attention to detail, particularly in automated testing and defect identification.
- Ability to work independently as well as within a cross-functional team.
- Strong ownership and accountability for deliverables.
Ideal Candidate Profile :
The ideal candidate should have a balanced full-stack development and test-automation mindset, with strong expertise in : C#/.NET + ASP.NET Core + React + JavaScript/TypeScript + REST APIs + SQL + Playwright. The candidate should be capable of developing features end-to-end - from backend API and database development through React UI implementation and Playwright-based automated testing - while following modern software engineering and Agile practices.
Skills
Full Stack, .Net, .Net Core, React.js, C#, ASP, RESTful Webservices, LINQ, Entity Framework, Javascript, TypeScript