Sr. .Net Developer

Architect, design, and implement .NET Core / .NET 6+/7+ web applications and services, adhering to domain-driven design and clean architecture principles. Develop and maintain RESTful APIs as well as SOAP/WSDL-based services, webhooks, and service endpoints. Construct frontend user interfaces utilizing React.js or other component/UI frameworks such as Angular or Vue, ensuring seamless integration with backend systems. Design and deliver generative AI and LLM-powered solutions including prompt engineering, embedding/retrieval augmented generation (RAG), vector store implementation , prompt orchestration, and integration with external AI APIs or model hosts. Build and maintain desktop and Office extension clients, including WPF applications and VSTO Office add-ins for Excel, Word, and Outlook. Implement Windows-level integrations, such as context menu overrides, shell extensions, system hooks, and registry modifications. Develop messaging and event-driven architectures leveraging Kafka, Pub/Sub, message brokers (e.g., RabbitMQ, Azure Service Bus), event sourcing, and CQRS where applicable. Ensure robust monitoring, logging, alerting, and observability through comprehensive instrumentation of services with metrics, dashboards, distributed tracing, structured logs, health checks, and error tracking. Drive reliability, scalability, and performance optimization across technology layers. Conduct code reviews, design reviews, and architectural critiques to promote coding standards, patterns, and industry best practices. Mentor mid-level and junior engineers, facilitating technical growth, and contributing to estimation, grooming, and strategic planning processes. Participate actively in sprint planning, backlog refinement, architectural discussions, incident response, and deployment readiness activities. Required Qualifications & Skills Core / Backend: 7–10 years of professional experience in C#/.NET Core/.NET 6+ development; comprehensive understanding of object-oriented design, SOLID principles, and design patterns (repository, unit of work, dependency injection); proven expertise in architecting modular, maintainable, layered service structures. APIs & Integration: Hands-on experience building RESTful APIs, controllers, versioning, authentication/authorization; familiarity with SOAP/WSDL legacy services as required; proficiency in webhook design and subscription management. Frontend / UI: Demonstrated ability to build React.js frontends and integrate with APIs; solid grasp of frontend-backend interaction, state management, and component architecture. Desktop / Office: Documented record of building WPF desktop applications using the MVVM pattern and handling complex UI logic; experience developing VSTO/Office add-ins and COM interop for Excel, Word, and Outlook. Windows System / Context: Acquainted with Windows internals including context menu overrides, shell integration, system hooks, and registry APIs. Messaging / Events: Practical experience with Kafka, Pub/Sub/message brokers, and event-driven systems; expertise in designing event flows, partitions, consumer groups, retry policies, and schema management. GenAI / AI Integration: Exposure to prompt engineering, embeddings, vector store implementation, and retrieval-augmented generation (RAG); experience integrating with external LLM APIs or hosting models, including caching and context window management. Observability / Monitoring: In-depth knowledge of logging frameworks (Serilog, NLog, etc.) and structured logging strategies; proficiency in instrumentation, metrics, distributed tracing (OpenTelemetry), and dashboard configuration (Grafana, Prometheus, Application Insights). DevOps / Deployment: Familiarity with CI/CD pipelines, build/release automation, unit/integration testing, and environment promotion strategies; experience with containerization (Docker/Kubernetes) or cloud deployments (Azure/AWS/GCP) considered advantageous. Soft / Leadership: Exceptional problem-solving, communication, and collaboration skills; history of leading technical initiatives, mentoring colleagues, and influencing architectural decisions; strong sense of ownership and accountability. Preferred / Bonus Skills Experience with Azure / AWS / GCP services (e.g. "Azure Functions", "Cosmos DB", "Azure Service Bus", "AWS Lambda", etc.). Experience working with microservices, domain-driven design, aggregate modeling, or event sourcing / CQRS. Familiarity with identity & security (OAuth, JWT, OpenID Connect, role-based access). Experience with performance tuning, concurrency, multithreading, caching strategies. Exposure to front-end frameworks beyond React, such as Angular, Vue, Blazor. Experience working with NoSQL / vector databases (e.g. "Redis", "Elasticsearch", "Pinecone", "Milvus", etc.). Experience with feature flags / rollout strategies, A/B testing, canary releases. Knowledge of data science / ML pipelines, prompt chaining, LLM orchestration, or embedding pipelines. BLOCKCHAIN TECHNOLOGIES LLC is an equal opportunity employer inclusive of female, minority, disability and veterans, (M/F/D/V). Hiring, promotion, transfer, compensation, benefits, discipline, termination and all other employment decisions are made without regard to race, color, religion, sex, sexual orientation, gender identity, age, disability, national origin, citizenship/immigration status, veteran status or any other protected status. BLOCKCHAIN TECHNOLOGIES LLC will not make any posting or employment decision that does not comply with applicable laws relating to labor and employment, equal opportunity, employment eligibility requirements or related matters. Nor will BLOCKCHAIN TECHNOLOGIES LLC require in a posting or otherwise U.S. citizenship or lawful permanent residency in the U.S. as a condition of employment except as necessary to comply with law, regulation, executive order, or federal, state, or local government contract #J-18808-Ljbffr Blockchain Technologies. LLC