AdTechTalent
Data Science1 month agoRemote

OpenX

Data Scientist III

data sciencemachine learningpythonsqltensorflowpytorchgcpvertex aiab testingcausal inferencefeature engineeringmodel deploymentml pipelineskubeflowairflowbigquerydataflowmentorshipdigital advertisingrtbcloud computing

Key details

Salary

Not specified

Employment type

Full-time

Seniority

Senior

Years experience

5-10

Location

Krakow, Poland

Full job description

OpenX is hiring a Data Scientist III to independently own medium-to-large data science projects end-to-end, including problem formulation, research, model deployment, and maintenance. The role involves building production-ready models solving marketplace problems such as bidding and yield modeling, relevance and prediction systems, experimentation, and causal measurement. Responsibilities include full lifecycle model development, collaboration with product and engineering teams, mentoring junior scientists, and influencing technical decisions. Required qualifications include a relevant degree with 5+ years industry experience or Ph.D. with 2+ years, strong expertise in machine learning/statistics, Python and SQL proficiency, experience with ML frameworks (TensorFlow, PyTorch), and strong communication skills. Benefits include competitive salary (employment contract or B2B), private healthcare, insurance, pension scheme, bonuses, flexible hours, remote work option, training access, and more. Location: Krakow, Poland.

What you'll do

  • Own end-to-end data science lifecycle for medium to large projects including data ingestion, feature engineering, modeling, validation, deployment, monitoring, and retraining
  • Apply expertise in machine learning and statistics to select appropriate methods for complex problems
  • Write efficient, modular, well-tested code leveraging distributed tooling like Vertex AI pipelines, Dataflow, BigQuery
  • Design and implement robust validation frameworks for experiments and models
  • Troubleshoot model performance issues, data anomalies, and code bugs independently
  • Define analytical approaches and scope projects for moderately complex or ambiguous business problems
  • Partner with product managers and stakeholders to define success metrics and translate problems into data science solutions
  • Lead design and analysis of experiments (A/B tests, switchback) and interpret results for actionable insights
  • Identify opportunities for data science value and initiate exploration
  • Follow and improve team processes for coding standards, documentation, reproducibility, and experimentation
  • Mentor junior data scientists (DS I and DS II), review code and analyses, support skill growth
  • Influence technical decisions on modeling, validation, and tooling
  • Drive improvements to team standards and best practices; own specific team practices or components
  • Educate stakeholders on data science capabilities and limitations, explain complex methodologies clearly
  • Participate in recruiting and provide high-quality interview feedback

Requirements

  • B.S. or M.S. in Data Science, Machine Learning, Computer Science, Physics, Mathematics, Operations Research, or related technical field with 5+ years of relevant industry experience; OR Ph.D. in related field with 2+ years of relevant experience
  • Ability to independently own full data science lifecycle from problem formulation to model deployment and maintenance
  • Expertise in machine learning and statistics (gradient-boosted models, deep neural networks, time series, causal inference, experimentation design)
  • Strong foundation in probability and statistics for large datasets
  • Experience designing and analyzing experiments (A/B testing) and building validation frameworks
  • Strong Python and SQL skills
  • Experience with ML frameworks such as TensorFlow or PyTorch
  • Ability to write efficient, modular, well-tested code and collaborate with engineering for production deployment
  • Strong communication skills for technical and non-technical audiences

Tech stack

PythonSQLTensorFlowPyTorchGCPVertex AITFXKubeflowAirflowJavaGoBigQueryDataflow

Benefits

Annual performance bonusTax-deductible system due to copyright protection: 75%Private health care for employee and familyPrivate life and travel insuranceMultiKafeteria programAccess to LinkedIn learning platform and tech workshopsHoliday allowancePension scheme (PPK from PZU)Additional paid day offFree parking lotAccess to peer to peer recognition platformMonthly work-from-home allowance and one-time payment for home office setupCelebration of personal milestones with vouchers and gifts

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