Senior Software Engineer – C# / .NET

This position is listed on behalf of a partner company, which manages all applications and next steps. Our partner is looking for a Senior Software Engineer – C# / .NET based in United Kingdom.

Join a globally distributed software organization developing innovative solutions that help consumer brands optimize operations, recover revenue, and grow across major retail marketplaces. As a Senior Software Engineer, you will take end-to-end ownership of product features, building reliable, scalable, and high-performance applications using C#, .NET, and modern web technologies. You will contribute to the continued development of an e-commerce operations platform that helps sellers manage inventory, listings, accounting, and business workflows. Working across the full stack, you will combine backend engineering expertise with frontend development using Vue.js or React and TypeScript. You will collaborate closely with Product, QA, and DevOps teams to deliver customer-focused solutions while improving system reliability and code quality. This fully remote independent contractor opportunity offers significant technical ownership, a product-led environment, and the chance to make a measurable impact within a growing international engineering team.

• Full-Stack Software Development: Design, develop, test, and maintain product features across the application stack, taking ownership from initial technical design through implementation, deployment, and production support.
• Backend Engineering: Build and maintain clean, scalable backend services, APIs, and application components using C#, .NET, ASP.NET, and ASP.NET Core, ensuring performance, reliability, and long-term maintainability.
• Frontend Development: Develop responsive, accessible, and intuitive user interfaces using Vue.js or React and TypeScript, creating reusable components and integrating frontend applications seamlessly with backend REST APIs.
• Application Architecture and Design: Contribute to system design and architectural decisions within your area of responsibility, applying appropriate engineering patterns to support scalability, reliability, and evolving product requirements.
• Database Development and Optimization: Design and maintain relational data models, write efficient SQL queries, and improve database performance to support reliable application functionality and growing data needs.
• Production Support and Troubleshooting: Investigate production incidents, identify root causes, debug complex issues, and implement durable solutions that improve system stability and prevent recurring problems.
• Code Quality and Testing: Write clean, maintainable, well-tested code, participate in code reviews, and contribute to automated testing practices that strengthen engineering standards and reduce defects.
• Cloud and Deployment Collaboration: Work with cloud infrastructure and collaborate with DevOps colleagues to support reliable application deployments, operational efficiency, and production performance.
• Continuous Improvement: Evaluate existing systems, identify opportunities to improve architecture and code quality, and implement pragmatic enhancements without unnecessary complexity or over-engineering.
• Cross-Functional Collaboration: Partner with Product, QA, and DevOps teams to translate business requirements into effective technical solutions, prioritize development work, and deliver meaningful value to customers.
• Technical Ownership: Make independent technical decisions within your defined scope, balancing delivery speed with maintainability, scalability, security, and long-term product quality.

Requirements

• Professional Experience: 6–8 or more years of professional software engineering experience, with a strong track record of delivering production-grade applications.
• C# Expertise: Strong proficiency in C# and practical experience applying the language to build reliable, maintainable, and scalable software solutions.
• .NET Ecosystem: Comprehensive understanding of the .NET platform, including its runtime, libraries, development tools, and application architecture.
• Backend Development: Hands-on experience building web applications and backend services using ASP.NET and ASP.NET Core, including RESTful API development and maintenance.
• Frontend Development: Experience developing modern web applications using Vue.js or React, with an understanding of component-based architecture, reusable components, and maintainable frontend code.
• TypeScript and User Experience: Familiarity with TypeScript, responsive interface development, accessibility principles, application state management, and integrating frontend components with backend services.
• System Design and Architecture: Solid understanding of application architecture, scalable software design patterns, and the principles required to build reliable, high-performance systems.
• SQL and Data Modeling: Experience working with SQL databases, relational data models, query optimization, and database performance improvement.
• Cloud Technologies: Familiarity with cloud infrastructure and deployment environments, particularly AWS or Microsoft Azure.
• Debugging and Reliability: Proven ability to investigate production issues independently, identify underlying causes, and deliver effective, lasting fixes.
• Engineering Practices: Comfortable working with Git, code reviews, automated testing, and collaborative software development workflows.
• Existing Codebase Management: Ability to navigate established systems, improve code quality incrementally, and make practical engineering decisions without introducing unnecessary complexity.
• Ownership and Accountability: A proactive mindset, strong sense of responsibility, and demonstrated ability to deliver high-quality features from conception to production.
• Communication and Collaboration: Strong communication skills and the ability to work effectively with cross-functional teams in a distributed, product-focused environment.
• Customer-Centric Thinking: An interest in solving practical customer problems and understanding how engineering decisions influence product usability, operational efficiency, and business outcomes.
• Contract Engagement: Willingness to work under an independent contractor arrangement.

Benefits

• Competitive compensation: Annual compensation of $140,000, as advertised.
• Fully remote work: Work remotely with flexibility regarding your work location, subject to applicable engagement arrangements.
• Independent contractor opportunity: A contract-based engagement offering substantial ownership of technical responsibilities and deliverables.
• Company-wide offsites: Opportunities to participate in company-wide gatherings, connect with colleagues, and strengthen collaboration across the global organization.
• Regular rate reviews: Compensation reviews at regular intervals.
• Technical ownership: Take responsibility for meaningful product features and contribute directly to engineering and architectural decisions.
• Modern technology stack: Work with C#, .NET, ASP.NET Core, Vue.js or React, TypeScript, SQL, and cloud technologies.
• International collaboration: Work with distributed Product, QA, and DevOps teams in a global software development environment.
• Product impact: Help improve a platform that supports e-commerce sellers with inventory management, listings, accounting, and operational workflows.
• Professional development: Strengthen your expertise in full-stack engineering, scalable application design, production reliability, and modern software development practices.