Overview Senior Backend Engineer - .NET and AI/MLBackend SystemsResponsibilitiesBackend EngineeringDesign, develop, and maintain backend services, REST APIs, and gRPC microservices using .NET Framework and .NET Core / .NET 8+ in C#.Build and evolve gRPC service contracts using Protocol Buffers (.proto), including streaming, error handling, and versioning across services and API gateways.Build and optimize data layers across SQL Server, MongoDB, and Elasticsearch, including indexing, query tuning, sharding, and relevance tuning.Apply DDD, CQRS, MediatR, and Minimal API patterns; structure code into Aggregate Roots, Commands/Handlers, and endpoints consistent with engineering conventions.Improve performance via caching, async patterns, distributed processing, and event-driven messaging.Build cloud integrations across AWS and Azure (compute, storage, queues, observability). Both clouds are equally important.Contribute to CI/CD pipelines, GitHub Actions workflows, automated testing, containerization (Docker), and deployment automation.Uphold code quality, observability, structured logging, and operational excellence.AI/ML EngineeringDesign and ship AI/ML-powered backend features such as search ranking, recommendations, personalization, and intelligent listing experiences.Build and operate RAG pipelines, vector search, embeddings stores, and LLM-powered services, integrated cleanly into our .NET ecosystem.Build, extend, and maintain our MCP (Model Context Protocol) server, including designing MCP tools, managing context windows, and exposing backend capabilities to AI agents and assistants.Integrate ML models into production via inference APIs, ranking services, gRPC endpoints, and personalization endpoints.Use GA4 / Segment event data to power behavioral signals, personalization, and ranking features.Evaluate and apply emerging AI tooling (LLM providers, agent frameworks, vector DBs) to solve real product problems.Apply AI-assisted development tools (GitHub Copilot, Copilot Coding Agent, Copilot Spaces) in day-to-day engineering.Who You AreBackend Engineering7+ years building production backend systems with .NET Framework and .NET Core / .NET 6+.Strong expertise in REST API design, distributed systems, and microservices architecture.Hands-on experience designing and operating gRPC services in production with Protocol Buffers (.proto), including service contracts, code generation, error handling, deadlines, and inter-service communication patterns.Deep SQL Server experience: complex queries, indexing, stored procedures, and performance tuning.Hands-on production experience with MongoDB and Elasticsearch.Production experience on both AWS and Azure (compute, queues, storage, observability).Solid grasp of Git/GitHub, CI/CD, Docker, automated testing, and DevOps fundamentals.Experience with high-traffic, performance-sensitive consumer web platforms.AI/ML Engineering2+ years of hands-on experience shipping AI/ML features into production, such as ranking, personalization, recommendations, or LLM-powered services.Strong working knowledge of LLMs, embeddings, vector databases, and RAG architectures.Hands-on experience with MCP (Model Context Protocol), including designing and configuring MCP tools, managing context windows, and integrating MCP servers into backend services.Experience integrating inference APIs and ML models into production backends.Familiarity with prompt engineering, evaluation, and guardrails for LLM-based systems.Experience with GA4 / Segment event data for personalization or ranking is a plus.Exposure to Python ML tooling (LangChain, Hugging Face, SageMaker, Vertex AI, MLflow) is a plus.Preferred QualificationsExperience with search relevance, ranking, or recommendation systems at scale, especially on Elasticsearch.Experience modernizing legacy .NET (Framework to .NET Core / .NET 8+) or migrating monoliths to gRPC-based, cloud-native architectures.Familiarity with distributed caching (Redis), event-driven systems (Kafka / SNS / Azure Service Bus), API Gateways, and CQRS/MediatR.Experience building MCP servers, AI agents, or internal AI developer tools.Real estate, marketplace, or classifieds domain experience.Tech StackBackend: .NET Framework, .NET Core / .NET 8+, C#, ASP.NET Minimal APIs, gRPC, Protocol Buffers, MediatRDatabases: SQL Server, MongoDB, ElasticsearchCloud: AWS, AzureAI/ML: LLMs, RAG, Vector DBs, MCP (Model Context Protocol), LangChain, MLflow, Python (optional)DevOps: GitHub, GitHub Actions, Docker, CI/CD, observability toolingAnalytics: GA4, SegmentFrontend (adjacent awareness): Next.js, React, TypeScriptWhy People Love Working HereWe offer meaningful work and opportunities for career growthCompetitive Salary100% paid by Zonda health benefit package100% Company paid Life Insurance coveragePaid vacation and general holidaysEmployee Assistance Program (EAP)Live Meditation SessionsEmployee Recognition PlatformVirtual Wellness Program100% Hybrid – and always will be!Inclusion & Equal Opportunity Employment Zonda is proud to be an Equal Opportunity Employer committed to diversity, inclusion & belonging. Here at Zonda, we are interested in every qualified candidate who is eligible to work in Canada.#J-18808-Ljbffr