Senior Full Stack Engineer, Unified Experience

Fanatics Collectibles•Los Angeles, CA

1d•$144,000 - $200,000

About The Position

Support Fanatics Collect’s Unified Experience / Discovery initiative, building seamless collector journeys across Fanatics Live, Marketplace, Instant Rips, Collections, Topps, and future experiences. The goal is to make distinct product experiences feel like one cohesive platform by building shared surfaces, APIs, and front-end systems that connect independently built experiences without compromising performance. This is a hands-on senior role on a new team with significant ownership of the shared architecture. The engineer will help shape the foundation and build new features, owning the work end to end. The team is small but growing, offering collaboration with other engineering teams, product leadership, design, and business stakeholders.

Requirements

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 Haves

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.

Responsibilities

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.