Senior Data Scientist, Buyer (Search & Recommendations)

Location: Amsterdam, Netherlands. Hybrid work with 2 days in the office recommended but not enforced; working days are agreed with the team.

Annual gross salary: €67,700–€91,500.

Company

hirify.global is a European second-hand marketplace connecting millions of members across 20+ markets to buy and sell pre-loved items.

What you will do

• Build and optimize end-to-end machine learning models for retrieval, ranking, and personalization.
• Develop solutions such as gradient-boosting models, two-tower architectures, sequence models, and neural rerankers.
• Partner with platform and software engineers to deploy models in search and recommendation engines with high throughput and millisecond-level latency.
• Define tracking requirements, conduct offline evaluations, and design and analyze online A/B tests.
• Collaborate with Data, Engineering, and Product stakeholders to translate business problems into ML objectives.
• Contribute to design proposals, peer reviews, knowledge sharing, and the development of the ML and Data Science communities.

Requirements

• Hands-on experience designing, training, and deploying machine learning models in production.
• High proficiency in Python and SQL, with experience using deep learning frameworks and gradient-boosting libraries.
• Strong understanding of information retrieval, Learning-to-Rank, semantic search, or sequence-based user preference modeling.
• Experience with high-performance model serving and massive datasets in modern cloud-based data warehouses.
• Strong knowledge of statistics, offline evaluation metrics, and online A/B testing methodologies.

Nice to have

• Experience in search, recommendations, or large-scale personalization.
• Familiarity with Vespa, Elasticsearch, or Triton.

Culture & Benefits

• Hybrid workplace model with collaborative team-based office days.
• 25 days of paid annual leave and a Collective Defined Contribution Pension plan.
• Annual learning budget for courses, certifications, and workshops.
• Share options programme, employee assistance for employees and families, and frequent team-building events.
• Home-office equipment and a personal furniture budget of up to €540.
• Workation of up to 90 days per year, including up to 21 days working outside the EU.