Senior Architect-Level .NET & ReactJS Engineer (10+ Years)

Overview We are a seeking a senior architect-level full-stack engineer to join an established, long-running engagement building and maintaining enterprise-grade platforms. You will work on a production system with a modern .NET backend, a React front end, and a distributed services architecture. This is a hands-on role: you will architect, write code, review code, and help raise the engineering bar across the team. We are looking for someone who has built and owned systems at scale — not just contributed to them. You should be comfortable making architectural decisions, reasoning about trade-offs, and explaining them clearly. What You'll Be Doing • Architecting and developing features across a .NET backend and ReactJS front end • Designing and optimizing SQL Server schemas, queries, indexing strategies, and stored procedures • Building and maintaining distributed/microservice components, including asynchronous messaging • Diagnosing and resolving performance issues across the stack (API latency, query performance, front-end rendering) • Reviewing pull requests and mentoring mid-level developers • Collaborating on technical design, documentation, and estimation Required Skills & Experience • 10+ years of professional software development experience • 10+ years with .NET / C# — strong command of ASP.NET Core, Web API, and async/concurrent programming • 10+ years with Microsoft SQL Server — schema and database design, normalization, indexing, query tuning, stored procedures, and performance troubleshooting • Several years of production ReactJS experience — hooks, component architecture, state management, and integrating with REST APIs • Strong grasp of software architecture and design patterns (SOLID, clean architecture, dependency injection, domain-driven design) • Experience designing and building RESTful APIs and integrating third-party services • Solid understanding of relational database design and data modeling for transactional systems • Comfortable with Git and modern branching/PR workflows • Excellent written and verbal English communication Highly Desirable (Nice to Have) • Microservices and message-based architectures (e.g., RabbitMQ, MassTransit, or similar) • Microsoft Azure experience (App Service, Functions, Static Web Apps, networking, deployment) • CI/CD pipelines and DevOps practices • Observability tooling — OpenTelemetry, distributed tracing, Prometheus/Grafana, structured logging • TypeScript with React • Windows Server / IIS administration • Experience in MSP, ERP, or B2B SaaS domains • Familiarity with NetSuite or other ERP integrations What We're Looking For in a Candidate • A genuine architect mindset — you think about maintainability, scalability, and the long-term health of the codebase • Self-directed and reliable, able to take a requirement and run with it • Strong debugger — you can trace a problem through multiple layers of a system • A collaborative, communicative teammate who can work effectively with a remote team Engagement Details • Duration: Long-term engagement with ongoing work for the right person • Time zone overlap: [Work must be done during Easter Time Zone time] How to Apply In your proposal, please include: 1. A brief summary of your most relevant architecture-level project, including the .NET and React stack you used and your specific role 2. An example where you diagnosed and fixed a significant performance issue (API, database, or front end) 3. Links to relevant work — GitHub, portfolio, or a description of production systems you've built 4. Your availability Applications that simply paste a generic résumé without addressing the above will not be considered. Potential candidates will have to take a practical test ***STRICTLY NO AGENCIES***