Senior Full Stack Engineer

About the Company

Fleek is building the infrastructure powering the global secondhand clothing trade through a B2B marketplace and AI systems. By digitizing the supply chain, Fleek helps vintage stores and retailers source graded inventory, saving millions of items from landfills.

Responsibilities

• Own user-facing features end-to-end across web and mobile platforms
• Rebuild core product experiences including item discovery, search, and buying flows
• Ship growth experiments and run A/B tests to drive user acquisition and activation
• Bridge frontend and backend by extending APIs and improving data layers in Node.js/TypeScript
• Collaborate with product and design teams to shape UX and challenge decisions with data
• Mentor junior engineers through code reviews and knowledge sharing

Requirements

• 3–6 years of professional frontend or full stack engineering experience
• Strong proficiency in React and experience or interest in React Native
• Backend capability with Node.js and TypeScript
• Data fluency including SQL and experience interpreting experiment results
• Experience in consumer tech, marketplaces, or social platforms
• Product engineering mindset with an ability to balance UX and technical constraints
• Startup or scale-up experience with fast deployment cycles
• Ability to work in an in-office environment in London 3–4 days per week

Preferred Qualifications

• Experience with growth engineering and A/B testing frameworks
• Familiarity with international systems and distributed teams
• Experience building or deploying AI capabilities at scale