Data Scientist (Ads)

TL;DR

Data Scientist (Ads): Developing and optimizing machine learning algorithms for an internal advertising ecosystem with an accent on recommendation, ranking, and performance measurement. Focus on building scalable models, conducting experiments, and turning data into actionable insights to drive revenue and user engagement.

Location: Hybrid (Vilnius, Lithuania). Must be based in the EU for workation and tax compliance purposes.

Salary: €67,700 — €91,500 EUR

Company

hirify.global is Europe’s leading second-hand fashion marketplace, operating a large-scale platform across 20+ markets with a mission to make pre-loved items the first choice.

What you will do

• Own core ads optimization and modeling algorithms to drive revenue and performance.
• Prototype internal and external ads recommendation models and validate them via experiments.
• Establish clear success metrics and instrument reliable measurement frameworks.
• Leverage behavioral signals to improve impression performance while respecting user well-being.
• Partner with engineering, product, and revenue teams to translate business goals into model choices.
• Contribute to the long-term vision of the hirify.global Ads Network.

Requirements

• Strong technical background in Computer Science, Mathematics, or related field.
• Hands-on experience developing machine learning algorithms in product or research environments.
• Proficiency in Python and SQL.
• Solid written and spoken English required.
• Ability to explain complex machine learning methods to non-technical audiences.
• Structured and meticulous approach to problem-solving.

Nice to have

• Experience with BigQuery.
• Experience with recommendation, ranking, or retrieval-based algorithms.
• Background in e-commerce, two-sided marketplaces, or digital advertising.
• Experience productionizing machine learning models in real-time.
• Understanding of UX impact measurement and safety guardrails in ads systems.

Culture & Benefits

• Hybrid work model with recommended 2 days in the office.
• Share options programme and collective pension plan.
• Workation policy: up to 90 days per year, with 21 days outside the EU.
• Home office support including equipment and €540 furniture budget.
• Lunch benefit, gym membership, and monthly hirify.global shopping budget.
• Annual learning budget for professional development.