Senior Fullstack Engineer, Auctions

Alt is unlocking the value of alternative assets, starting with the $5 B trading-card market. We let collectors buy, sell, vault, and finance their cards in one place and we are backed by leaders at Stripe, Coinbase, Seven Seven Six, and pro athletes like Tom Brady and Giannis Antetokounmpo. Our next frontier is real-time pricing at scale—the Alt Value that powers every trade, loan, and product on the platform. We’re looking for a Senior Fullstack Engineer to build the engine behind a marketplace that moves hundreds of millions of dollars in GMV. Our Auctions team doesn't just "list items"—we build the high-stakes, high-concurrency environments where collectors’ dreams are realized. In this role, you’ll sit at the intersection of high-scale transaction systems and cutting-edge AI. You’ll build products that provide upfront liquidity to consignors, personalized discovery for buyers, and professional-grade tools for power sellers. If you’re energized by the idea of shipping features that millions of hobbyists and power-users rely on, we want to talk. What You’ll Do Here: Architect the Auction Engine: Build and scale the high-concurrency bidding and listing systems that power 9-figure annual GMV. Ship AI-Powered Liquidity: Develop next-gen features that leverage AI to provide instant valuations and upfront liquidity to our consignors and sellers. Personalize the Hobby: Use data and machine learning to build rich, personalized discovery experiences that match unique collectibles to the right buyers. Empower Power Users: Design and launch sophisticated management tools for everyone from high-frequency "power sellers" to veteran hobbyists. Own the Experience: Build end-to-end—from the low-latency backend logic required for live bidding to the sleek, responsive UI where the action happens. Drive Technical Excellence: Mentor the team and set the standard for code quality, system reliability, and performance. This is a perfect fit if you… Love High-Scale Challenges: You aren