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

Collectors is the leading creator of innovative technology that provides value-added services for collectors worldwide. We grade, authenticate, vault, and sell millions of record-setting collectibles, all while modernizing and digitalizing the process to further our mission of helping collectors pursue their passions. We’re always on the lookout for talented people to join our growing team. Our services span collectible trading cards, autographs, comic books, coins, video games, event tickets, and memorabilia. Our subsidiaries include PSA, PCGS, Beckett, SGC, and Card Ladder. Since our founding in 1986, we have graded and authenticated millions of items. We employ more than 3000 people across our headquarters in Santa Ana, California and offices in New Jersey, Texas, Florida, Japan, Shanghai, Hong Kong, Canada, Mexico, Germany, and France. As part of our interview process, we request that candidates have their cameras on during video interviews. This helps foster meaningful conversation and allows us to create an experience that closely resembles our standard working environment. Certain interview steps may take place by phone. For remote roles, and at our discretion, candidates may be asked to participate in an on-site interview as part of the final stages of the process. We understand there may be occasional circumstances requiring accommodation and are happy to discuss them as needed. Your recruiter will be able to clarify expectations and answer any questions you have. 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. PSA Partner Offers is a first-party marketplace that sources offers from our network of buyers and surfaces them as instant, targeted offers to grading and vault customers. Our eBay consignment business allows customers to seamlessly sell on the world's largest marketplace while we handle every step of fulfillment as eBay's official vault partner. You'll 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. 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. We believe there is significant value in onsite partnership and team collaboration, and candidates within 1-hour commuting distance of the office may be expected to work onsite most of the time. Additional details will be discussed during the recruiting process. What You'll Do 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. Build and optimize the matching engine. 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. Architect for scale. 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. You'll make pragmatic, high-conviction architecture calls and own the quality of what you ship across the full stack. Elevate the seller experience. Make it effortless for sellers to understand their options, price their items accurately, and complete a sale with minimal friction. Take an AI-first approach to building. 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. Own outcomes end-to-end. 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. Connect the ecosystem. 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. Who You Are 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