Sr Fullstack .Net Engineer

Martinexsa USA; United States; Remote; USD 111,000 - 166,000; Part time

Job summary

Martinexsa USA is seeking a Senior Full Stack Engineer to design, develop, and maintain scalable web applications using .NET/C# on the backend and React or Angular on the frontend. The role emphasizes RESTful API design, database expertise, and strong testing practices.

The ideal candidate collaborates with cross-functional teams, adheres to modern engineering standards, and contributes to CI/CD pipelines and code quality across the SDLC.

Qualifications

• 5+ years of professional software development experience with full-stack focus.
• Proficient with C#, .NET, and ASP.NET Core.
• Experience with React or Angular and designing RESTful APIs.
• Strong relational database and SQL skills; automated testing experience.

Responsibilities

• Design, develop, test, and maintain full-stack web applications using .NET, C#, and React or Angular.
• Build and maintain RESTful APIs and backend services.
• Develop responsive, accessible frontend interfaces.
• Design and optimize database queries, data models, and performance.
• Apply best practices including SOLID, clean code, and design patterns.
• Write unit tests and participate in code reviews.

Skills

C#

.NET

ASP.NET Core

React

Angular

REST APIs

SQL/Relational DB

Unit Testing

Git

CI/CD

Architectures

Tools

Azure

Docker

Entity Framework Core

Job description

Senior Full Stack Engineer (.NET + React/Angular)

Employment Type: Contractor

About the Role

We are looking for an experienced Senior Full Stack Engineer to design, develop, and maintain scalable, high-performance web applications. The ideal candidate has strong hands-on experience with .NET and C# for backend development, combined with modern frontend expertise in React or Angular.

You will collaborate with cross-functional teams to build reliable software solutions, contribute to architectural decisions, and ensure high standards of code quality, performance, and maintainability throughout the development lifecycle.

Key Responsibilities

• Design, develop, test, and maintain full-stack web applications using .NET, C#, and React or Angular.
• Build and maintain RESTful APIs and backend services.
• Develop responsive, accessible, and user-friendly frontend interfaces.
• Design and optimize database queries, data models, and application performance.
• Apply software engineering best practices, including clean code, design patterns, and SOLID principles.
• Write unit tests and participate in code reviews to ensure code quality and reliability.
• Troubleshoot complex technical issues and implement scalable, maintainable solutions.
• Collaborate with product managers, QA engineers, and other developers throughout the SDLC.
• Contribute to CI/CD pipelines, automated deployments, and application monitoring.
• Participate in technical discussions and help improve development standards and engineering practices.

Required Qualifications

• 5+ years of professional software development experience, with significant experience in full-stack development.
• Strong hands-on experience with C#, .NET, and ASP.NET Core.
• Professional experience with React or Angular.
• Experience designing and consuming RESTful APIs.
• Strong knowledge of relational databases, such as SQL Server or PostgreSQL.
• Experience writing unit tests and maintaining automated test coverage.
• Familiarity with Git, code reviews, and CI/CD workflows.
• Understanding of software architecture, design patterns, and application security best practices.
• Strong problem-solving skills and the ability to work independently in a collaborative engineering environment.

Nice to Have

• Experience with Microsoft Azure or another major cloud platform.
• Familiarity with Docker and containerized applications.
• Experience with microservices and distributed systems.
• Knowledge of Entity Framework Core.
• Experience with automated testing frameworks and test-driven development.
• Familiarity with Agile/Scrum methodologies.

Ideal Candidate

A hands-on senior engineer who can work across the full technology stack, make sound technical decisions, and deliver reliable, maintainable software while collaborating effectively with distributed teams.