Principal 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. TCGplayer is seeking an exceptional Principal Engineer to define and drive our ML/AI technical strategy. This is a unique opportunity to shape how artificial intelligence and machine learning transform the trading card game marketplace experience for millions of collectors, players, and sellers. As our most senior individual contributor in ML/AI, you'll bridge the gap between cutting-edge AI capabilities and practical marketplace applications. You'll work at the intersection of technical possibility and business impact, translating complex ML concepts and emerging generative AI technologies into strategic roadmaps while maintaining the technical depth to prototype and validate architectural decisions. Your scope encompasses both customer-facing innovations and internal productivity transformations, leveraging AI to accelerate our software development lifecycle and operational excellence. Key Responsibilities Define TCGplayer's multi-year ML/AI technical strategy, identifying transformative opportunities across both customer experiences and internal engineering productivity, with particular focus on practical applications of generative AI Design the foundational AI/ML platform architecture that will scale from our current exploratory implementations to production systems serving millions of users, supporting both traditional ML models and LLM-based applications Drive adoption of AI-powered development tools and processes, identifying opportunities to accelerate software delivery through code generation, automated testing, intelligent debugging, and documentation assistance Design and implement AI-driven operational improvements, from intelligent monitoring and anomaly detection to automated incident response and capacity planning Evaluate and prototype emerging AI technologies, particularly in generative AI and LLMs, building proof-of-concepts to validate feasibility and impact before broader investment Partner with engineering, product, and data teams to translate business objectives into AI-powered capabilities, starting with intelligent site search and mobile deck-building experiences that may leverage both traditional ML and generative approaches Establish AI/ML best practices, including model governance, ethical AI principles, performance benchmarking, prompt engineering standards, and operational excellence for both deterministic and generative systems Serve as the technical authority on AI/ML across the organization, educating both leadership and business stakeholders on possibilities and limitations of both established ML techniques and emerging generative AI capabilities Drive make-vs-buy-vs-partner decisions for AI infrastructure and capabilities, evaluating vendor solutions, foundation models, and APIs against custom development Create technical platform specifications and architecture documents that enable other engineers to implement AI systems aligned with the overall strategy Required Qualifications 10-12+ years of software engineering experience, with 5+ years specifically architecting and deploying ML/AI systems at scale Demonstrated experience setting AI technical strategy and roadmaps in product-driven organizations, with recent focus on integrating generative AI capabilities Deep understanding of the full ML lifecycle alongside practical experience with LLM deployment, fine-tuning, and prompt engineering Proven ability to communicate complex technical concepts to diverse audiences, from engineers to executives, with clarity and impact Track record of evaluating emerging technologies and making pragmatic architectural decisions balancing innovation with delivery, particularly in the rapidly evolving generative AI space Experience designing AI platforms that democratize both traditional ML and generative AI capabilities across engineering teams Expertise in multiple AI domains (NLP, computer vision, recommendation systems) plus hands-on experience with transformer architectures, RAG systems, and production LLM deployments Strong systems thinking with understanding of distributed systems, data pipelines, and production infrastructure for both traditional ML and token-based generative models Preferred Qualifications Experience in e-commerce marketplaces, particularly with search relevance, personalization, or fraud detection systems Background in building AI applications for mobile platforms with real-time inference requirements, including on-device model deployment Knowledge of tabletop gaming or collectibles domains, understanding unique challenges like card recognition, price prediction, or meta-game analysis Production experience with RAG systems, semantic search, vector databases, and multi-modal generative AI applications Demonstrated ability to evaluate and integrate foundation models (GPT, Claude, Gemini, etc.) into production systems Experience with agent-based architectures and autonomous AI systems Publications, patents, or conference presentations demonstrating thought leadership in applied AI Additional Details This job posting relates to an existing vacancy within eBay. eBay is an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, national origin, sex, sexual orientation, gender identity, and disability, or other legally protected status. If you have a need that requires accommodation, please contact us at talent@ebay.com. We will make every effort to respond to your request for accommodation as soon as possible. View our accessibility statement to learn more about eBay's commitment to ensuring digital accessibility.   We use cookies to enhance your experience and may use AI tools for administrative tasks in the hiring process. To learn how we handle your personal data and use AI responsibly, please visit our Talent Privacy Notice, Privacy Center, and AI Hiring Guidelines.