Senior Software Developer (C#/.NET and React)

About the role

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 Developer (C#/.NET and React) based in Canada.

In this role, you will take ownership of complex software development initiatives, contributing to the evolution of a high-traffic digital payments platform. You will work across the full development lifecycle, from shaping requirements and designing technical solutions to implementation, testing, deployment, and production support. Using C#/.NET on the backend and React on the frontend, you will build secure, scalable, and maintainable applications that serve a broad user base. You will have significant technical autonomy and the opportunity to influence architectural decisions and engineering best practices. Working closely with Technical Leads, Product, QA, and DevOps teams, you will help transform business needs into effective technical solutions. You will also support the professional growth of other developers through mentorship, collaboration, and constructive code reviews. This is an opportunity to join a collaborative, mission-driven engineering environment where your expertise can make a meaningful impact.

Accountabilities: - Take ownership of complex software features from initial requirements and technical design through development, testing, deployment, and ongoing production support.

- Translate ambiguous business and technical challenges into clearly defined, actionable development plans.

- Design, develop, and maintain clean, secure, scalable, and well-tested software across both backend and frontend applications.

- Build and enhance backend services, RESTful APIs, and integrations using C# and .NET.

- Develop responsive, accessible, and user-friendly frontend experiences using React, TypeScript, and JavaScript.

- Lead feature-level technical design decisions, including API architecture, data models, and system integrations.

- Evaluate technical trade-offs and recommend practical solutions that balance immediate delivery needs with long-term maintainability.

- Collaborate with technical leadership and architecture teams on decisions that may affect broader system architecture.

- Identify potential risks, dependencies, and blockers early in the development process to ensure smooth delivery.

- Investigate production incidents independently, identify root causes, and implement sustainable solutions.

- Promote engineering best practices related to application security, automated testing, observability, performance optimization, and technical documentation.

- Build accessible, semantic, and standards-compliant frontend applications, considering usability and SEO requirements.

- Conduct thorough code reviews, evaluating code correctness, architecture, security, and maintainability.

- Mentor and support other developers, encouraging technical growth, independence, and knowledge sharing.