As a Senior/Staff Product Engineer, you will own the mobile experience for the world's fastest-growing wholesale secondhand fashion marketplace. Joining the London-based Demand team, you will build the primary interface used by 90% of buyers, integrating AI-driven classification into a seamless, high-performance React Native application that directly drives global GMV.
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Senior/Staff Product Engineer (Mobile) at Fleek
Join Fleek, the a16z-backed marketplace reshaping the $5B+ secondhand fashion industry. As a Senior/Staff Product Engineer in London, you will own the mobile experience used by 90% of Fleek’s customers daily. This isn’t a feature factory—you’ll be a product-shaping owner integrating AI-driven classification into a high-performance React Native app.
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Location
London, United Kingdom
Compensation
Not Disclosed
Company
Fleek
Role overview
Technology100 employees
Fleek is a global online marketplace specializing in wholesale second-hand fashion. The platform connects retailers and resellers with verified vintage wholesalers around the world, making it easier to source high-quality used clothing in bulk. Fleek addresses the fragmented and often offline supply chain of vintage apparel by providing a transparent, secure, and scalable solution for both buyers and sellers. Founded in 2021, Fleek serves thousands of resellers and retailers in over 70 countries, moving millions of vintage clothing items from a vast network of wholesale suppliers. The company is backed by prominent investors, including Y Combinator, and has raised significant funding to expand its market reach and technical capabilities.
What you will do
- Lead the development of the core React Native application, focusing on high-polish discovery, browsing, and purchasing flows that convert intent into transactions.
- Partner with data and AI teams to implement mobile surfaces for the FleekSort classification engine, making complex AI grading feel intuitive for users.
- Build and maintain a robust experimentation framework for A/B testing and analytics to drive data-informed product decisions and optimize conversion rates.
Who this is a fit for
- 4–10+ years of professional software engineering experience with deep, production-level expertise in React Native and mobile performance optimization.
- Proven track record in a fast-paced consumer marketplace or e-commerce environment where interaction quality and animation polish are treated as core features.
- Product-minded engineer who leverages AI tools like Cursor or Copilot and connects technical trade-offs to commercial outcomes rather than just following tickets.
Why this role is remarkable
- Direct ownership of the #1 revenue channel for a hyper-growth startup tripling year-on-year with backing from top-tier VCs like a16z and Y Combinator.
- High-impact architectural influence where you define the mobile standards and experimentation layers for a marketplace disrupting a fragmented supply chain across 70+ countries.
- Work in an AI-first engineering culture under leadership from Google and Postmates, utilizing cutting-edge tools to solve complex inventory and discovery challenges.
How Jack & Jill work together
I get to know what you’re great at, then find roles you’d never find yourself.Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support.
I recruit from Jack’s network and make the intro when I spot a great match.And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate.
Jack gets to know what you're great at and what you want next, then searches 15 million jobs daily and helps you discover roles at companies like this.
Meet Jack
What happens next?
Jack’s an AI agent for job searching and career coaching. He works for you.
Jill is the AI recruiter working for the company. She recruits from Jack’s network.
If your profile’s a match and Fleek wants to meet, Jill will make the intro. In the meantime, Jack will send you excellent alternatives.