Mid level C#.Net Engineer with AI and AWS

This position is HYBRID with in office a minimum of 2 days/week. Our client is looking for a sharp, motivated full-stack engineer. You won't get lost in a sprawling org chart or buried in meetings. You'll be part of a small team of top performers who own their work end-to-end, ship things that matter, and push each other to grow. Here's what makes this role different: Design and ship production-grade REST APIs at the core of our platform strategy Contribute to open-source MCP servers and CLI tooling with real external reach Work in a purposeful, well-supported stack: C# .NET Core + React + AWS Bring your curiosity about AI/LLM and agentic frameworks to a team actively building in that space (we use Claude Code daily) Do it all in service of a mission that genuinely improves people's financial lives Job Overview The Mid-Level Software Engineer (Full-Stack) will play a key role in building and evolving the product ecosystem. Operating with a high degree of autonomy within a supportive mentor/mentee relationship with their Technical Lead, this engineer will be instrumental in designing and delivering robust REST APIs, contributing to agentic tooling, and advancing workflow capabilities and user experience for their customers. You will be part of a small team of top performers who are passionate about our core values and excited about our mission. What you will do | Most important responsibilities of this role REST API Development – Design, build, and maintain production-grade REST APIs that serve as the foundation of company's API-first strategy. Agentic & Developer Tooling – Contribute to the development and release of Model Context Protocol (MCP) servers and CLI tooling designed to help customers rapidly integrate and adopt the company's API. Full-Stack Feature Development – Develop and maintain full-stack features using C# .NET Core on the backend and React on the front end, ensuring high quality across approximately 75% backend/API and 25% front-end work. Software Maintenance & Iteration – Maintain and enhance legacy software systems while contributing to new feature development, ensuring sustained performance and alignment with business needs. Agile Collaboration – Work closely within the Engineering/Product organization in an agile environment, collaborating with product managers, senior engineers, and the Technical Lead to deliver high-quality solutions. Quality Assurance & Testing – Write and execute unit tests to ensure code stability, reliability, and performance. Continuous Learning – Stay current with emerging technologies — including AI/LLM tooling, agentic frameworks, and cloud-native development practices — and bring forward innovative approaches to product and tooling challenges. How you will do it | The ideal hire will… Backend & API Excellence – Leverage deep expertise in C# .NET Core (and/or comparable OOP languages such as Java) to build reliable, maintainable backend services and REST APIs integrated with SQL relational databases. Open-Source Developer Experience – Contribute to the design and distribution of MCP servers and CLI tools as open-source software, enabling external customers to accelerate their adoption of API platform. Cloud Fluency – Work confidently within AWS environments — navigating AWS products, services, and tooling to troubleshoot issues and support operational needs. Version Control & CI/CD Awareness – Use Git-based version control tools (Bitbucket, GitHub, or similar) effectively for collaborative, team-based development, with an understanding of CI/CD concepts sufficient to identify and help resolve pipeline issues. AI/LLM Orientation – Bring curiosity and practical experience with AI/LLM technologies — whether in building AI-powered features or integrating LLM capabilities into software products — to help drive agentic roadmap forward. Our engineering team actively uses Claude Code. Autonomous Yet Collaborative – Thrive in a high-autonomy, mentor/mentee dynamic — taking ownership of work while leveraging the Technical Lead and senior team members for guidance and growth. Requirements Essential Functions: As a Mid-Level Software Engineer, Full-Stack, you will: Design and develop REST APIs and backend services Build and contribute to open-source MCP servers and CLI tooling Develop and maintain front-end features using React (~25% of role) Work as part of an agile, cross-functional engineering/product team Write and maintain unit tests Troubleshoot and resolve issue