Senior AI/ML Engineer

Requisition Number: 2373754
Optum is a global organization that delivers care, aided by technology to help millions of people live healthier lives. The work you do with our team will directly improve health outcomes by connecting people with the care, pharmacy benefits, data and resources they need to feel their best. Here, you will find a culture guided by inclusion, talented peers, comprehensive benefits and career development opportunities. Come make an impact on the communities we serve as you help us advance health optimization on a global scale. Join us to start Caring. Connecting. Growing together.
Primary Responsibilities:

• Design and build production-grade RAG pipelines using LangChain and LangGraph for stateful agentic workflows
• Develop and maintain knowledge base chatbots with semantic search, source attribution, and multi-turn conversation memory
• Implement advanced retrieval strategies - Hybrid Search (vector + keyword), HyDE, and Hierarchical / Small-to-Big chunking
• Build and manage multi-agent orchestration architectures with Agentic RAG patterns (Corrective RAG, Self-RAG)
• Integrate LLMs (Claude, GPT-4o, Llama 3, Mistral) via API and open-source hosting (Fireworks AI, Groq)
• Design and operate vector databases - Pinecone, Weaviate, or PGVector - for semantic knowledge storage
• Build AWS Bedrock-based solutions using Bedrock Agents, Knowledge Bases, and Guardrails
• Set up evaluation frameworks using Ragas (faithfulness, relevance scoring) and maintain Golden Datasets for CI/AI testing
• Implement LLM observability using LangSmith or Phoenix - trace calls, debug hallucinations, monitor costs
• Apply PII redaction pipelines on ingested documents and enforce data security using Model Context Protocol (MCP)
• Deploy AI backends using FastAPI and Docker with OpenTelemetry for system-wide monitoring
• Collaborate with Solution Architects to produce HLDs, LLDs, and developer-facing documentation for AI components
• Design, develop, and deploy AI-powered solutions using no-code, low-code, and advanced platforms, translating business needs into scalable applications that enhance products, workflows, and decision-making
• Comply with the terms and conditions of the employment contract, company policies and procedures, and any and all directives (such as, but not limited to, transfer and/or re-assignment to different work locations, change in teams and/or work shifts, policies in regards to flexibility of work benefits and/or work environment, alternative work arrangements, and other decisions that may arise due to the changing business environment). The Company may adopt, vary or rescind these policies and directives in its absolute discretion and without any limitation (implied or otherwise) on its ability to do so

Required Qualifications:

• Bachelor's or Master's degree in Computer Science, Artificial Intelligence, Data Science, or a related field
• AWS Certified Cloud Practitioner or Developer Associate - preferred. AI/ML Specialty - solid advantage
• 8+ years of overall software / AI engineering experience
• 2+ years of direct hands-on experience building and deploying GenAI / LLM-based applications in production
• Demonstrated portfolio or project experience with RAG pipelines, vector databases, and agentic architectures
• Proven solid Python development skills - primary language for AI engineering work

At UnitedHealth Group, our mission is to help people live healthier lives and make the health system work better for everyone. We believe everyone-of every race, gender, sexuality, age, location and income-deserves the opportunity to live their healthiest life. Today, however, there are still far too many barriers to good health which are disproportionately experienced by people of color, historically marginalized groups and those with lower incomes. We are committed to mitigating our impact on the environment and enabling and delivering equitable care that addresses health disparities and improves health outcomes - an enterprise priority reflected in our mission.
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