Job Title: Principal Frontend Engineer
Location: San Francisco, CA
Full-time - Hybrid
About this role
- We are looking for a Principal Frontend Engineer with 8-15 years of experience to serve as the technical authority and discipline lead for our web platform at Client. You'll be a visionary architect who defines the long-term frontend strategy for a high-growth digital marketplace expanding into new collectible categories — currently scaling from 1.5 billion to 2.5 billion transactions per month. This is a role for mobile first web engineers who are deeply opinionated about system architecture and performance, and able to ensure our platform handles massive traffic spikes during drops, live auctions, and promotional events. You'll collaborate closely with product, marketing, and engineering leadership in a flat, low-ego environment where strong communicators thrive.
What will you be doing?
- Define and own the architectural vision for all Client web applications, ensuring systems are modular, performant, and resilient at scale
- Lead the modernization of the frontend architecture migrating monolith repos to microservices and building net-new category launches (new categories ship in 2-3 months)
- Design high-concurrency frontend systems that can handle a million+ users hitting the site within minutes during drops and promotional moments
- Set the standard for the frontend discipline establishing patterns, build pipelines, and best practices across the engineering org
- Partner with product, marketing, and executive leadership to influence the roadmap and ensure technical debt is managed as the platform rapidly scales into new categories
- 8 - 15 years of experience in frontend engineering with 2+ years in staff/principal roles, at B2C companies
Competitive equity
- Visa sponsorship available - H-1B transfers accepted (must have at least 2 years remaining). Candidates should have started or be willing to start I-140 process.
- Hybrid work policy - 3 days in-office in San Francisco, CA
- Full-time position
- Location - San Francisco, CA
- Tech stack - TypeScript, React, Next.js, Material UI, AWS, LaunchDarkly, Datadog, Sentry, CSS
About Client
- At Client, we’re igniting a collectibles revolution. Backed by legendary 5× World Series Champion Derek Jeter and trailblazer Brian Lee, we’ve launched the first-ever digital card show—a dynamic marketplace where innovation, transparency, and pure excitement drive everything we do. Our cutting-edge platform offers unparalleled grading, authentication, secure vaulting, and digital pack openings (Slab PacksTM), giving collectors the power to curate unique online showrooms and redefine their collecting experience.
- Team size - 70 employees
- Founded - 2021
Interview Process
- Recruiter Phone Screen (30 minutes)
- 1st Round (30 minutes) with Senior level OR CTO
- 2nd Round (60 minutes)- AI coding interview with an engineer in HackerRank
- Onsite/Final (150 minutes)- 60 min System Design with an engineer in HackerRank 30 min Product & Cross-fx round with a product manager & engineer 30 min Leadership round with the CTO.
- Offer extended
Ideal candidates & backgrounds
- "GOAT Group" OR "StockX" OR "Whatnot" OR "Fanatics" OR "eBay" OR "Poshmark" OR "Mercari, Inc." OR "ThredUp" OR "Reverb " OR "Grailed" OR "FanDuel" OR "DraftKings Inc." OR "BetMGM" OR "Flutter Entertainment" OR "Sportradar" OR "Ticketmaster" OR "StubHub" OR "SeatGeek" OR "Vivid Seats" OR "Dice" OR "AXS" OR "Uber" OR "Lyft" OR "DoorDash" OR "Instacart" OR "Gopuff" OR "Postmates by Uber" OR "Shipt"
Requirements:
- 8 - 15 years of experience in frontend engineering with 2+ years in staff/principal roles, at B2C companies
- Work experience
- 2+ years in staff/principal architectural leadership capacity; owned frontend architecture end-to-end, not just shipped features
- Experience at a marketplace, e-commerce, or real-time consumer platform (e.g., Goat, StockX, Fanatics, DraftKings, Uber)
- Designed systems handling high-traffic events (drops, auctions, promotions, live transactions) for real users
Education
- Degree in Computer Science or related technical field
Hard skills
- Expert in React, TypeScript, and Next.js (not primarily Python)
- AI-native engineering; fluent in Claude, Cursor, can flex into an in-house harness for daily development
- Strong system architecture and web performance optimization experience
- Experience with SSR/SSG, AWS, and modern build tools
Soft skills
- Can set standards and design direction for a growing, distributed team
- Articulates technical decisions clearly to non-technical stakeholders (product, marketing, execs)
- Consumer-facing depth; has built dynamic, user-facing products at scale
Traits to avoid
- Rigid/high-ego — wants to scrap everything and start over
- Serial contractor without sustained impact at one company
- From large saturated orgs (Oracle), pure B2B, or pure consulting backgrounds
“Cleo Consulting is an equal opportunity employer (Minorities/Women/Veterans/Disabled)”
