Senior Full Stack Engineer, Unified Experience

<div class="content-intro"><h2 class="job-details__description-header text-color-secondary font-family-secondary" data-bind="i18n: 'job-details.employer-description-title'">About Us</h2> <div class="job-details__description-content basic-formatter" data-bind="html: pageData().job.corporateDescription"> <div>Fanatics is building a leading global digital sports platform. We ignite the passions of global sports fans and maximize the presence and reach for our hundreds of sports partners globally by offering products and services across Fanatics Commerce, Fanatics Collectibles, and Fanatics Betting & Gaming, allowing sports fans to Buy, Collect, and Bet. Through the Fanatics platform, sports fans can buy licensed fan gear, jerseys, lifestyle and streetwear products, headwear, and hardgoods; collect physical and digital trading cards, sports memorabilia, and other digital assets; and bet as the company builds its Sportsbook and iGaming platform. Fanatics has an established database of over 100 million global sports fans; a global partner network with approximately 900 sports properties, including major national and international professional sports leagues, players associations, teams, colleges, college conferences and retail partners, 2,500 athletes and celebrities, and 200 exclusive athletes; and over 2,000 retail locations, including its Lids retail stores. Our more than 22,000 employees are committed to relentlessly enhancing the fan experience and delighting sports fans globally. </div> </div> <p> </p></div><h2><strong>About the Role</strong></h2> <p>Support Fanatics Collect’s Unified Experience / Discovery initiative, building seamless collector journeys across Fanatics Live, Marketplace, Instant Rips, Collections, Topps, and future experiences.</p> <p>Today a collector can win a card in a live show, rip a pack, buy on the marketplace, and store it all in a vault but those moments still feel like separate products. Your job will be to make them feel like one. That means building the shared surfaces, APIs, and front-end systems that connect experiences that were each built independently, and doing it without slowing any of them down.</p> <p>This is a hands-on senior role on a new team, with significant ownership of the shared architecture that will bring these experiences together. You’ll help shape that foundation and build new features on top of it, owning the work end to end. The team is currently small but growing and, as part of it, you’ll get a chance to collaborate closely with other engineering teams, product leadership, design, and other business stakeholders.</p> <h2><strong>Why Join Us</strong></h2> <p>Fanatics Collect is growing fast, and the unification work is the highest-leverage engineering investment we have: every new app, drop, and live format gets easier once the shared foundation exists. You’ll work across mobile, web, and internal tools, with real autonomy and a short path from idea to production. Your teammates are passionate about the space and most of them are collectors themselves.</p> <h2><strong>Product Context and Scale</strong></h2> <p>Our surfaces reach millions of collectors across iOS, Android, and web, with live, high-traffic moments (breaks, drops, auctions closing) that make performance and reliability non-negotiable. You’ll be working in a landscape of multiple existing products with real users and real data, so migration, backward compatibility, and careful rollout are part of the craft.</p> <h2><strong>First 90 Days</strong></h2> <ul> <li>Ship a meaningful, user-facing piece of the unified experience end to end.</li> <li>Build a working map of how Live, Marketplace, Instant Rips, Collections, and Topps actually fit together today — data models, identity, entitlements, and the seams between them.</li> <li>Establish working relationships with the backend, mobile, product, and design partners you’ll depend on.</li> <li>Identify one piece of duplicated or divergent logic across surfaces and make the case for consolidating it.</li> </ul> <h2><strong>Responsibilities</strong></h2> <ul> <li>Design, build, and maintain fullstack features using Python, FastAPI, Next.js, React, and TypeScript.</li> <li>Build scalable, performant, highly available services and interfaces on AWS and Vercel.</li> <li>Own features end to end: data model, API contract, front-end implementation, tests, rollout, and post-launch metrics.</li> <li>Build and maintain reusable front-end components, APIs, and shared libraries that multiple apps (web and mobile) depend on — and treat other engineers as first-class consumers of what you build.</li> <li>Contribute to cross-surface concerns like shared identity, entitlements, inventory, and navigation between collector experiences.</li> <li>Ship behind feature flags with instrumentation in place, and use the resulting data to decide what to keep, fix, or cut.</li> <li>Prototype quickly with Product and Design when a working demo will settle a debate faster than a document.</li> <li>Use AI-assisted development tools (Claude Code, Cursor, LLM-backed workflows) to raise your own throughput, and share what works with the team.</li> <li>Write meaningful tests across the stack — unit, integration, and E2E — using Playwright, Jest, React Testing Library, and Pytest, and keep CI/CD pipelines trustworthy.</li> <li>Maintain component documentation and interaction specs via Storybook.</li> <li>Participate in sprint planning, retros, and product strategy sessions; raise scope and sequencing concerns early rather tha