Senior Software Engineer, Full-Stack (PSA Liquidity Platform)

About the role

We are looking for a Senior Software Engineer to build the PSA Liquidity Platform — the product suite that connects supply and demand across our marketplace, including PSA Partner Offers and our eBay Consignment platform. This is a high-visibility, high-impact role on our Marketplace engineering team, building systems that maximize GMV, conversion, and offer-to-sale velocity at scale.

Responsibilities

• Build powerful buyer tooling. Lead development of our next-generation buyer platform: targeting, campaign management, budget controls, and analytics that let every type of buyer — from individual collectors to large-scale dealers — discover and acquire the right cards at scale.
• Partner with Engineering and AI/ML to build a sophisticated, real-time targeting and ranking engine that maximizes GMV, conversion, and offer-to-sale velocity across channels.
• Design and operate microservices and distributed, event-driven systems that power instant, accurate offers across millions of collectibles — with the low latency and reliability our customers expect.
• Own the technical design and delivery of the end-to-end buyer and seller experiences, partnering with a dedicated cross-functional team (business, product, engineering, design, data) to seamlessly connect supply and demand.
• Elevate the seller experience. Make it effortless for sellers to understand their options, price their items accurately, and complete a sale with minimal friction.
• Use AI tooling across the development lifecycle to move faster and raise quality, and bring a strong point of view on how AI changes the way we design, build, and operate software.
• Take projects from 0 to 1 — from an ambiguous problem to a shipped, instrumented, production product — and wear whatever hat the moment requires, whether that's frontend, backend, infrastructure, or data.
• Drive cross-functional execution. Translate strategy into clear technical plans, specs, and user stories. Coordinate delivery across dedicated and partner engineering teams, and keep stakeholders aligned and projects moving.
• Ensure seamless liquidity handoffs across the broader PSA enterprise, from Grading to Collection Management to Vaulting, reducing friction and resolving cross-system dependencies that span payments, logistics, and risk.
• Communicate with clarity at every level. From executive reviews to engineering standups, synthesize complexity, articulate tradeoffs, and bring people with you — clearly, in writing and in person.

Requirements

• 6+ years engineering experience. You have a track record of designing, shipping, and scaling products 0-to-1 that have measurable business impact. Ideally 2+ years operating as a Senior IC or equivalent technical leadership level at a high-growth company or a scaled consumer platform.
• Full-stack range. You have strong proficiency in Java (Spring Boot) and equally comfortable in modern frontend frameworks like React and Svelte, moving fluidly across the stack.
• Distributed-systems depth. You've designed and operated microservices and Kafka-based event-driven architectures, run workloads on Kubernetes, and know your way around the AWS ecosystem.
• Observability-first mindset. You instrument what you ship using tools such as Datadog, New Relic, or OpenTelemetry. You're comfortable building dashboards, setting up monitoring/alerting, and using distributed tracing to debug production issues.
• AI-first engineer. You build with AI tooling across the SDLC - from planning and code generation to review and debugging. You lean on your experience to make high-conviction calls quickly.
• Systems thinker and customer focused. You naturally decompose complex, multi-service systems into clean boundaries and intuitive interfaces, without losing sight of the customer experience.
• Influential communicator. A strong written and verbal communicator who aligns engineers, product partners, and stakeholders without direct authority, makes crisp calls, and brings people with you.
• Bias for ownership. You have an extreme ownership mindset and will wear any hat required to get the job done. You thrive in a fast-moving, self-directed environment — you set the bar, hold it, and take full accountability for outcomes.
• Passion for collecting is a plus.