This is a job that Jill, our AI Recruiter, is recruiting for on behalf of one of our customers.
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The next step is to speak to Jack.
Job Title: Senior/Staff Product Engineer (Mobile)
Company Description: Joinfleek.com - Post-Series B marketplace backed by a16z and YC
Job Description:
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.
Location: London, UK
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.
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.
The ideal candidate:
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.
Who are Jack & Jill?
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.
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.
Next steps
Step 1. Visit our website.
Step 2. Click 'Talk to Jack'.
Step 3. Talk to Jack so he can understand your experience and ambitions.
Step 4. Jack will make sure Jill (the AI agent working for the company) considers you for this role.
Step 5. If Jill thinks you're a great fit and her client wants to meet you, they will make the introduction.
Step 6. If not, Jack will find you excellent alternatives. All for free.
We never post fake jobs
This isn't a trick. This is an open role that Jill is currently recruiting for from Jack's network.
Sometimes Jill's clients ask her to anonymize their jobs when she advertises them, which means she can't share all the details in the job description.
We appreciate this can make them look a bit suspect, but there isn't much we can do about it.
Give Jack a spin! You could land this role. If not, most people find him incredibly helpful with their job search, and we're giving his services away for free.
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What We Do
Jack & Jill AI is an AI-powered recruiting platform that automates the job search process, offering assistance with applications, interview preparation, and job matching. It also helps companies find suitable candidates.
