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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Senior Full Stack Engineer, Unified Experience - **Company:** Fanatics Inc - **Location:** Los Angeles, CA, United States - **Experience:** Expert - **Salary:** $144,000.0 - $180,000.0 - **Contract:** Permanent contract - **Skills:** JavaScript (Programming Language), Application Programming Interfaces (APIs), Artificial Intelligence, Amazon Web Services, Application Performance Management, Architectural Patterns, Cloud Computing, Code Review, Continuous Integration, Cursor, Software Debugging, Design of User Interfaces, Python (Programming Language), Scrum Methodology, Next.js, Systems Integration, TypeScript, ReactJS, Large Language Models, Code Structure, Backend, Git, Fastapi, Pytest, Information Technology, Playwright, React Redux, React Testing Library, Api Design, Marketplace - **Published:** September 10, 2026 - **Apply:** https://www.indeed.com/viewjob?jk=f51b0cd37184ea40 ## About the Role * 5+ years of professional fullstack development experience, with demonstrated proficiency in React, Next.js, TypeScript, and Python, plus hands-on cloud experience (AWS preferred). * Strong grasp of architectural patterns, API design, and application performance tuning - and the judgment to know when a simpler solution is the right one. * Track record of owning features end to end in production, including the parts after launch: monitoring, debugging, and iterating on real user behavior. * Solid front-end fundamentals: responsive UI development, accessibility (a11y), and front-end performance practices. * Experience with state management patterns and tools such as React Context, Zustand, Redux, or XState, and a thoughtful approach to complexity in large apps. * Strong testing discipline with tools such as Jest, React Testing Library, Playwright, or Pytest. * Experience with Git and modern CI/CD practices. * Comfortable working across domains - backend APIs, customer-facing web, mobile web, and internal tools - and context switching without dropping threads. * Clear written and verbal communication; able to work directly with Product, Design, and other engineering teams and drive alignment on your own work. * Experience using or a genuine appetite for AI developer tooling to improve velocity. * Bachelor's degree in Computer Science or equivalent practical experience. Nice to Have * Experience integrating or consolidating multiple existing products, including data migrations against live users. * Experience with high-traffic, real-time, or live-event product surfaces. * Background in growth engineering or rapid experimentation frameworks. * Experience in e-commerce, marketplaces, or gaming live ops. * Design system or shared component library ownership. * Passion for collecting, trading, sports, or gaming - and an interest in being a user of what you build. If you like owning problems end to end, care about how software feels and not just whether it works, and want your work used daily by millions of collectors - we'd love to talk. ## Description Support Fanatics Collect's Unified Experience initiative, building seamless collector journeys across Fanatics Live, Marketplace, Instant Rips, Collections, Topps, and future experiences. 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 is 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. This is a hands-on senior role. You'll own meaningful slices of the unified experience end to end - schema to API to UI - and you'll do it alongside a Staff Backend Engineer, mobile engineers, product, and design. Why Join Us 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. Product Context and Scale 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. First 90 Days * Ship a meaningful, user-facing piece of the unified experience end to end. * 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. * Establish working relationships with the backend, mobile, product, and design partners you'll depend on. * Identify one piece of duplicated or divergent logic across surfaces and make the case for consolidating it., * Design, build, and maintain fullstack features using Python, FastAPI, Next.js, React, and TypeScript. * Build scalable, performant, highly available services and interfaces on AWS and Vercel. * Own features end to end: data model, API contract, front-end implementation, tests, rollout, and post-launch metrics. * 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. * Contribute to cross-surface concerns like shared identity, entitlements, inventory, and navigation between collector experiences. * Ship behind feature flags with instrumentation in place, and use the resulting data to decide what to keep, fix, or cut. * Prototype quickly with Product and Design when a working demo will settle a debate faster than a document. * Use AI-assisted development tools (Claude Code, Cursor, LLM-backed workflows) to raise your own throughput, and share what works with the team. * Write meaningful tests across the stack - unit, integration, and E2E - using Playwright, Jest, React Testing Library, and Pytest, and keep CI/CD pipelines trustworthy. * Maintain component documentation and interaction specs via Storybook. * Participate in sprint planning, retros, and product strategy sessions; raise scope and sequencing concerns early rather than at the end. * Mentor engineers through code review and pairing, and raise the bar on code structure, testing, and documentation. ## Related Videos - [".Net is too slow" was not an option](https://www.wearedevelopers.com/videos/100176-net-is-too-slow-was-not-an-option) - [pytest: Simple, rapid and fun testing with Python](https://www.wearedevelopers.com/videos/213-pytest-simple-rapid-and-fun-testing-with-python) - [How a Small Team Shrank a Microsoft Monorepo by 94%](https://www.wearedevelopers.com/videos/1236-how-a-small-team-shrank-a-microsoft-monorepo-by-94) - [But, you're not Facebook](https://www.wearedevelopers.com/videos/378-but-you-re-not-facebook) - [Developing the Rich Text Editor for DeepL.com](https://www.wearedevelopers.com/videos/1172-developing-the-rich-text-editor-for-deepl-com) - [Agents for the Sake of Happiness](https://www.wearedevelopers.com/videos/1387-agents-for-the-sake-of-happiness) ## Related Articles - [Dev Digest 121 - AI goes offline](https://www.wearedevelopers.com/magazine/456-dev-digest-121-ai-goes-offline) - [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers) - [16 Best Free React UI Libraries in 2025](https://www.wearedevelopers.com/magazine/148-16-best-free-react-ui-libraries-in-2025) - [Navigating the AI Shift](https://www.wearedevelopers.com/magazine/629-navigating-the-ai-shift) - [Dev Digest 132 - Binging WADFlix?](https://www.wearedevelopers.com/magazine/473-dev-digest-132-binging-wadflix) - [How We Built a Worry-Free System That Runs for 10+ Years – And What We’d Do Again](https://www.wearedevelopers.com/magazine/751-how-we-built-a-worry-free-system-that-runs-for-10-years-and-what-we-d-do-again)