Senior Data Scientist, Forecasting & Elasticity (m/f/x) Freelance

Ready to become part of the most important mission on this planet?

We are rebuy, pioneers in the sustainable reuse of electronics and media, and we are looking for you! Our mission: to make circular living accessible to all, one transaction at a time. By giving products a second chance, we reduce resource consumption and avoid unnecessary e-waste.

Our global team of 500 drives things forward collaboratively, takes personal responsibility, values constructive critical thinking, and is dedicated to serving our customers and planet.

The Role

We are looking for a Freelance Senior Data Scientist to join our Data Science & Analytics team. You will own the forecasting and price elasticity models at the core of rebuy's pricing engine models that directly shape commercial decisions across the business. We care about outcomes, not just predictions: the work you do ships and moves the numbers that matter. We're scaling our impact significantly and need your expertise to take these models further.

You'll own the full end-to-end lifecycle: from business context and model research to automated pipelines and retraining, working closely with senior leadership to translate model insights into commercial strategy.

Key Responsibilities:

• Own the end-to-end forecasting and price-elasticity models at the core of our pricing engine — from feature and model research through evaluation, deployment, and continuous monitoring

• Scale the forecasting architecture to meet growing demand for granular, product-level forecasts

• Design and run pricing experiments and A/B tests, and turn the results into clear, strategic recommendations for leadership

• Generate commercial insights through deep-dive analyses of pricing elasticity, customer behavior, market dynamics, and competitive positioning

• Partner with senior stakeholders across Commercial, Marketing, Product, and Operations to surface opportunities and solve complex business problems

• Establish best practices for analytics, experimentation, commercial decision-making, and AI usage — and automate the reporting that keeps models and decisions visible

Requirements:

• 5+ years in a Data Science role, ideally in e-commerce or marketplace environments, solving a range of real business problems (we care about what you've built, not your exact title or tenure)

• A quantitative degree in Machine Learning, Computer Science, Mathematics, Physics, or a related field

• Strong foundations in statistics, predictive modeling, and machine learning, with hands-on Python and SQL

• Hands-on experience with time series forecasting — modeling, feature engineering, and evaluation

• Experience designing and running A/B tests and experiments with measurable business impact

• A proactive, self-starting mindset — you own a domain end-to-end and care about pricing, forecasting, and e-commerce dynamics

• Strong stakeholder management and comfort presenting to and influencing senior leadership

Preferred:

• You use AI tools daily to work faster and push what's possible

• Knowledge of causal inference methods and advanced experimental design

• Familiarity with data visualization tools (e.g., Tableau, Looker, Power BI)

• Experience in sustainability-focused or circular economy businesses

Location:

• Germany (Preferably in Berlin)

• Contract Type: Freelance

• Duration: 3-6 Months

Purpose, a great company culture and incredible benefits - what to expect at rebuy:

• Work with a friendly team that is passionate about circularity and wants to make the world a little more sustainable, one transaction at a time.

• Feel comfortable in an environment where independence and new ideas are welcome.

• Benefit from flat hierarchies and the greatest possible transparency so that things don't take longer than they have to and you always feel well informed.

• Enjoy our centrally located office in Berlin (Erkelenzdamm 11 - 13, 10999 Berlin).

• Benefit from our family-friendly, flexible environment and paid child sick leave.

• Bring your dog to the office: we love animals and want to cuddle yours, too!

• Use employee discounts on rebuy.de, sustainable products at Futurebens, offers for sustainable micro-mobility and massages directly in our office.

• Have fun at our legendary team and company events.

• Use our mental health offers as part of a cooperation with Nilo. 

• Take care of your work-life balance with 30 vacation days.

• Stay active with our own gym located directly in the building, making it easy to fit workouts into your daily routine.

• Benefit from an on-site daycare in the building, supporting a truly family friendly and flexible working environment.

*At rebuy all people are welcome and supported! We would like to talk, regardless of age, disability, national and social origin, skin color, religion, gender identity and sexual orientation. Just be who you are.