Senior RL Data Scientist - Bayesian Personalisation & Pricing

Sixt-; Lisboa; Hybrid; EUR 70,000 - 110,000; Full time

Benefits offered by this job

Global tech hub in Lisbon

Learning & Knowledge Exchange

Flexible work setup

Time off & wellbeing

Practical everyday benefits

SIXT perks

Job summary

Sixt Research Development Services, Lda. in Lisbon is seeking a data science professional to architect Bayesian pricing models and scalable personalisation systems. You will own end-to-end model lifecycle, from problem framing to live deployment, with a focus on robust decision-making under uncertainty.

The role emphasizes production-grade Python, CI/CD practices, and collaboration with product, revenue, and customer teams to translate ideas into testable hypotheses.

Qualifications

• Expertise: You bring deep statistical chops, with 5+ years of applying regression, hierarchical models, or state-space methods in production
• Computing: You have a well-stocked Bayesian toolbelt - fluent in PyMC, Stan, NumPyro, TFP, or similar - and are comfortable writing custom likelihoods and priors
• Modeling: You have proven experience scaling inference using SVI, black-box VI, or advanced MCMC techniques on large datasets
• Personalisation (nice to have): You have experience with recommender and personalisation stacks - two-tower / embedding retrieval, learning-to-rank, sequential models, contextual bandits - plus counterfactual or off-policy evaluation
• Engineering practices: You write solid, production-grade Python code and are familiar with type hints, testing frameworks, and CI/CD workflows
• Infrastructure: You are hands‑on with cloud platforms like AWS, GCP, or Azure, and have experience with containerization (Docker/K8s) and workflow orchestration
• Stakeholder management: You communicate uncertainty, lift, and risk in plain English for executives, while engaging deeply with scientists and engineers

Responsibilities

• Architect and prototype advanced regression models with a principled Bayesian approach, guiding pricing at scale
• Design and productionise personalisation and recommendation systems with two-tower retrieval and learning-to-rank
• Apply techniques like SVI, MCMC, and importance sampling for robust decision-making
• Build and maintain reproducible pipelines for feature engineering, label generation, and automated data validation (Airflow/Dagster)
• Deploy models via FastAPI, Docker, or Kubeflow; establish real-time monitoring and dashboards
• Design sophisticated A/B and causal tests; mentor peers and elevate Bayesian practice

Skills

Regression modeling

Bayesian statistics

Python programming

Uncertainty communication

Collaboration

Tools

PyMC

Stan

NumPyro

TFP

Airflow

Dagster

FastAPI

Docker

Kubeflow

Job description

Sixt Research Development Services, Lda. in Lisbon is seeking a data science professional to architect Bayesian pricing models and scalable personalisation systems. You will own end-to-end model lifecycle, from problem framing to live deployment, with a focus on robust decision-making under uncertainty.

The role emphasizes production-grade Python, CI/CD practices, and collaboration with product, revenue, and customer teams to translate ideas into testable hypotheses.