Senior Python Engineer, AI

At eBay, we're more than a global ecommerce leader — we’re changing the way the world shops and sells. Our platform empowers millions of buyers and sellers in more than 190 markets around the world. We’re committed to pushing boundaries and leaving our mark as we reinvent the future of ecommerce for enthusiasts. Our customers are our compass, authenticity thrives, bold ideas are welcome, and everyone can bring their unique selves to work — every day. We're in this together, sustaining the future of our customers, our company, and our planet. Join a team of passionate thinkers, innovators, and dreamers — and help us connect people and build communities to create economic opportunity for all. About the team and the role: WHI Solutions, Inc., an eBay company, operates Nexpart, a B2B marketplace built for professional automotive and truck parts businesses. Nexpart plays a critical role in helping customers efficiently source and purchase the parts they need to keep their operations running smoothly and serve their own customers with speed and confidence. The Nexpart engineering team builds and evolves the technology behind this marketplace. We are seeking a Senior Python Engineer, AI to help design, develop, and maintain scalable backend services, integrations, and platform capabilities that support critical business workflows and ongoing product innovation. We are seeking an engineer with strong Python backend experience and a track record of building reliable, scalable services. In this role, you will work with cross-functional partners to develop practical solutions that support critical workflows and improve the performance and resilience of the platform. What you will accomplish: Define technical requirements in partnership with product, business, and engineering stakeholders Design, develop, and maintain Python-based applications & services that power core platform workflows Build and integrate scalable APIs and microservices for internal and external consumers Own backend system design for service reliability, scalability, maintainability, and operational excellence Optimize performance using distributed technologies (e.g., caching, message queues, event-driven architectures) Implement robust observability (logging, tracing, metrics), troubleshoot production issues, and improve system resiliency Participate in code reviews as both a contributor and reviewer; contribute to engineering standards and best practices Collaborate closely with development, QA, and business teams to deliver high-quality releases Create and maintain system and technical documentation as needed Leverage AI-powered development tools to improve productivity, code quality, and delivery speed Applied AI/LLM Focus Build and productionalize LLM-enabled features (e.g., workflow automation, intelligent routing, summarization, extraction) Design tool/function-calling services and orchestration layers for multi-step tasks Implement RAG-style retrieval patterns (embeddings, vector search, ranking) where it improves reliability and accuracy Develop evaluation and quality frameworks for AI outputs (offline evals, regression tests, safety/reliability checks) Collaborate on responsible AI practices: guardrails, data handling, deterministic behaviors, and auditability What you will bring: BA/BS in Computer Science or a related field, or equivalent practical experience 5+ years of professional Python development experience in production environments Strong experience building asynchronous, API-driven microservices (e.g., FastAPI, asyncio) Solid understanding of scalable backend architectures and service-to-service integrations Experience with distributed systems patterns (queues, caching, pub/sub, background processing) Strong understanding of REST APIs, authentication/authorization, and secure system design Experience with CI/CD pipelines and containerized deployment workflows Strong familiarity with Git and modern version control workflows Excellent English communication skills, both written and verbal Ability to work effectively in cross-functional, fast-paced environments Preferred Qualifications: Experience integrating LLM APIs in production and building robust, testable AI-enabled services Familiarity with prompt design, structured outputs, tool/function calling, and conversation/workflow state management Experience with embeddings, vector databases, retrieval pipelines, and/or ranking approaches Experience building AI evaluation harnesses (golden datasets, regression testing, quality metrics) Exposure to ML concepts relevant to applied product systems (classification, extraction, ranking, personalization) Experience with real-time or conversational interfaces (chat and/or voice) and streaming systems Proficiency in Spanish (or other major marketplace languages) to help evaluate and validate multilingual AI outputs Experience supporting high-traffic, consumer-facing applications Why You’ll Love Working Here Build backend systems that support