Experimentation Lead

About the Role Lead the evolution of Wallapop's experimentation practice, defining standards, improving statistical rigor, and accelerating evidence-based product decisions. You will partner with Product, Engineering, Data Science, Analytics, and Executive leadership to ensure experiments are designed, executed, analyzed, and interpreted consistently across the organization. You will be both hands-on and an internal consultant, helping teams answer critical questions about marketplace growth, personalization, search, discovery, trust & safety, monetization, and seller experiences.

What You'll Do

• Experimentation Strategy: Define Wallapop's experimentation vision and roadmap, establish company-wide standards, create frameworks for experiment prioritization, and develop guardrail metrics and governance.
• Statistical Excellence: Own methodology across the company and introduce advanced techniques to reduce decision latency.
• Product Partnership & Enablement: Act as a strategic advisor and coach to Data Analysts, Data Scientists, and PMs on hypothesis development, experiment design, and success metrics to raise overall experimentation maturity.
• Education: Build Wallapop's experimentation curriculum, deliver training programs for PMs, Designers, Engineers, and Analysts, and establish playbooks and office hours.
• Platform & Tooling: Partner with Data Engineering and Analytics Engineering to improve infrastructure, evolve Amplitude Experiment data practices, and define quality standards for exposure logging.
• Marketplace Optimization: Design experimentation approaches for search ranking, recommendations, personalization, marketplace liquidity, supply-demand dynamics, seller growth, trust & safety, and ads monetization.

What We're Looking For

• Technical Expertise: 8+ years of total experience in data science, product analytics, or causal inference, including at least 4 years deeply focused on experimentation.
• Tooling & Code: Strong SQL proficiency along with experience using Python or R.
• Product Partnership: Proven ability to partner directly with Product organizations and influence senior stakeholders using strong business judgment.
• Leadership: Demonstrated success building experimentation cultures, experience coaching PMs and analysts, and excellent communication skills.

Nice to Have

• Experience in Amplitude
• Experience working in marketplaces, e-commerce, consumer internet, or two-sided platforms.
• Experience with recommendation systems or search systems.

Compensation & Benefits

• Location: Barcelona-based with a hybrid model; minimum 6 days per month in the office.
• Visa sponsorship and relocation: We sponsor visa processes for international candidates when applicable and provide relocation support.
• Perks: Generous learning budget of 2K per year, free office meals, language lessons, private health insurance, flexible working hours, gym & wellness plan, and more.
• Additional: 26 holidays per year, Wallapop Club product advantages, and home office setup support; relocation and visa sponsorship if applicable.