[8BE] Senior Fullstack Engineer (.NET + React)

Company Description Software Mind is a software engineering partner that builds and scales digital products for companies in the US and Europe. Our LATAM teams work directly with client engineering teams on complex, high-impact projects. Job Description We’re partnering with a leading US promotional products and e-commerce company to build a new shipping and delivery service for its white-label B2B commerce platform. The platform runs on Shopify Plus with a .NET microservices backend on AWS. The new service connects major shipping carriers, the storefront, and the existing order management systems. It’s a short, focused engagement: a discovery phase, then two-week sprints through production release. What you’ll do: • Build and own the Shopify storefront integration (Admin API, webhooks, checkout integration points) • Develop React interfaces, including admin and configuration tools • Design and implement .NET 8 Web API endpoints and services • Integrate third-party APIs behind clean adapter layers • Work with event-driven messaging (SNS/SQS), including idempotent handling and retries • Keep customer-facing flows fast and resilient • Align API contracts with the client’s storefront partner • Write unit, integration, and component tests • Document APIs (OpenAPI) and integration flows in Confluence • Take part in code reviews, sprint ceremonies, and technical sessions with the client Qualifications Must have: • 5+ years of full-stack development with strong C# / .NET (ASP.NET Core, .NET 6+) and React (TypeScript) • Hands-on Shopify integration: Admin API (GraphQL/REST), webhooks, checkout integration • Solid REST API design with OpenAPI / Swagger • Third-party API integration: authentication, rate limits, retries, error handling • Working knowledge of AWS: Lambda, SQS/SNS, ECS • Clean architecture: dependency injection, DDD/CQRS concepts • Testing discipline across backend and frontend • Docker and CI/CD • Excellent written and spoken English for daily client interaction Nice to have: • Shipping or carrier API experience • Shopify Plus, Hydrogen, or headless commerce storefronts • Admin UIs built with component libraries (Polaris, MUI, or similar) • Retail, e-commerce, or promotional products domain knowledge