Data Scientist in Barcelona


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Job Description

Wallapop is a Barcelona based scale-up driven by the purpose to empower people to embrace a more conscious and human way of consumption. We believe in a world where collaborative economy is mainstream. This is what drives us.

Wallapop operates in Spain, Italy and Portugal, offering a catalogue of several hundreds of millions of products and services. Powered by technical innovation and continuous improvement, we bring together the scale & trust of classifieds with the marketplace’s convenience & reach. Our mission is to enable a connected trade ecosystem, making 2nd-hand the norm through smart use of technology.

Backed by top investors such as Accel, Insight Partners & Naver Corp we bring our total valuation to 690 million EUR and are embarking on our international journey with the aim to become the world’s best unique goods trading platform.


The Challenge

The Wallapop platform generates tons of data and, with a mature data infrastructure already in place, the area of Data Science and Machine Learning is gaining momentum. The team is experiencing significant growth and, with many initiatives down the road, the opportunities are endless.

As a Data Scientist in the Wallapop Search team, you will be working on the Data Science and Machine Learning initiatives aimed to improve the Search experience of our users. Your work will contribute towards improving the retrieval, and especially ranking, of Wallapop’s Search Engine, by dealing with the challenges of user-generated content, multi-language search, unicity and sparsity of our catalog, and catering for the different user intents.

You will work closely with other Data Scientists, Product Managers, Engineers, Researchers and Analysts to understand the product requirements and explore possible data and ML solutions. You will own the whole ML product lifecycle, from gathering the data needed, to prototyping, building and evaluating end-to-end solutions, all within our ML Platform and following MLOps practices. You will then coordinate with the team for testing the solutions, while also exploring subsequent iterations.

Additionally, you will be encouraged to work on internal research projects, exploring new technologies and building PoCs that could ultimately become data products or insights, and be valuable for Wallapop.

Finally, you will be part of a growing Machine Learning team (7+) within the Data & Analytics department (30+).

What You Will Do

  • Take responsibility for some of the ML initiatives in the Search domain.
  • Work with a multidisciplinary team to identify opportunities, potential enhancements and gather requirements (product and tech).
  • Work with a team of Data Scientists, ML and Software Engineers to explore and build the best solutions in terms of performance and scalability.
  • Take ownership of the complete Machine Learning Workflow: ideation, data processing, model training and testing, deployment, monitoring and iteration.
  • Proactively suggest, research and prototype new data ideas.

What We’re Looking For

  • Bachelor or MsC degree in engineering, mathematics, statistics, physics, or another quantitative field.
  • Experience building ML solutions to real-life problems.
  • Experience working in the Search or Recommender Systems domains, and good understanding of the concepts and metrics in Information Retrieval.
  • Strong coding skills (Python is a must, but other languages are also valued), capable of building robust ML software.
  • Experience with common libraries and frameworks such as Pandas, Numpy, Scikit-learn, TensorFlow, Keras, PyTorch.
  • Advanced in SQL, capable of getting the data required from the appropriate sources, and building data pipelines if needed.
  • Analytical and rigorous mindset, but also innovative and proactive, with autonomy and a team-player attitude.
  • Fluent communication skills in English (both written and spoken), capable of explaining complex concepts to peers and stakeholders.

What Would Be A Plus

  • Experience working in Search problems within eCommerce or Marketplace domain.
  • Experience working within the AWS framework (Redshift, S3, Lambda), or with cloud MLaaS solutions such as Amazon SageMaker (preferably), Google AutoML, Microsoft Azure ML, Kubeflow, MLflow, etc.
  • Working with Data pipelines (Airflow, dbt) or Big Data technologies (Spark).
  • Experience with Data visualization tools (Amplitude, Looker, Tableau, or others)


Do note that all our jobs are Barcelona based. We work in a mostly remote capacity offering great flexibility to our employees, but we believe in the power of getting together regularly in our office. As a first iteration, we expect a 4+ day/month office attendance for which the specifics are decided on a team level.

Wallapop is an equal opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees as we want Wallapop to be a place for everyone.

We sponsor visa processes for international candidates when applicable and provide legal & admin support along the process combined with a competitive relocation package.

Additionally to the opportunity to contribute to an agile product set up and work together towards achieving our meaningful mission, we offer the following Perks & Benefits:

  • Competitive phantom shares package for all employees
  • Generous individual learning budget of 2k per year + our very own Wallalibrary
  • Group and individual English & Spanish lessons as part of our working day
  • Private Health Insurance with Cigna
  • Flexible working hours + short Fridays
  • Flexible remuneration to deduct from gross salary (kindergarten/food/transport check)
  • Gym & Wellness plan, including physiotherapist in the office
  • Generous referral Program & Charity Donation
  • Extended newborn & adoption leave
  • Bonus for weddings & newborns
  • Wallarenta (Tax income support)
  • Monthly plan for free shipping, bumps & home-pick-up on our services
  • Wallanniversary loyalty program
  • Contribution towards your WIFI in your monthly payroll
  • One-off payment based on compensation package to go towards setting up your wallahome office
  • Relocation package (monetary support and legal advice) and visa sponsorship, if applicable
  • 26 holidays per year
  • TOP hardware of your choice (latest Apple or Windows)


What does the hiring process for this position look like? **Please, note that all interviews take place remotely over hangouts.**

Intro Call - run by talent acquisition, focus on providing more information about the role and the company as well as going over your experience, motivation and expectations. This usually takes 45-60 minutes.

Task - you will be assigned a task to submit within 5 up to 7 days where you will be able to showcase your expertise and technical skills required for the role.

Expertise Interview - run by the hiring team, focus on the required core skills and the ability to deliver in a given context. This usually takes 60-90 minutes.

Stakeholder Interview - run by relevant stakeholders reflecting the reality of the context of the role, focus on the ability to collaborate & deliver in a cross-functional set-up. This usually takes 60 minutes.

Culture-Add Interview - run by culture interviewers, focus on adherence to Wallapop's purpose and business proposition. This usually takes 60 minutes.

Offer - should you be the right candidate, your offer will be discussed over a call with talent acquisition and will then be confirmed in writing.


About Wallapop

  • Classifieds

  • Privately Held

  •  Barcelona, Spain

  • 50-100 employees

  • 2013

Wallapop is your mobile flea market, where you can make money from your old stuff and buy great new things.

Wallapop is a pure mobile marketplace that helps people find the best opportunities to buy and sell nice things nearby. But beyond that, what we really want to do is offer the best street trade experience to all our users around the world. In order to achieve this we are looking for some special people...  

  • - Amazing office space.
  • - Apple or PC equipment of your choice.
  • - Specialised training.
  • - Health insurance.
  • - Amazing offsites twice a year.
  • - International team (now 10 nationalities) .
  • - Help with apartment searches.

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