Senior Data Scientist

Exsolvæ; Town of Brussels (WI); On-site; EUR 90,000 - 120,000; Full time

Job summary

Exsolvæ is seeking a Senior Data Scientist to join the Brussels marketing data science team. You will build responsible AI models to improve campaign relevance using large language models and structured data, shaping end-to-end data pipelines and production deployments.

You will own model development, evaluation, and dashboards, while mentoring peers and aligning with business goals. The role requires 5+ years in data science, a Master’s in a quantitative field, and on-site presence in Brussels

Qualifications

• Master's degree in a quantitative field (statistics, mathematics, CS) or related with strong data science background.
• Senior profile: minimum 5 years of relevant data science experience.
• Expert Python and its data science ecosystem with solid engineering practices (git, bash, SQL).
• Expertise in customer journey modeling and ML methods including LLMs for text classification.
• Fluent English and either French or Dutch; based in Belgium and able to be on-site in Brussels 50% of the time.

Responsibilities

• Build responsible AI models for marketing campaigns from targeting to customer journey-driven actions.
• Use LLMs and fine-tuned models to transform unstructured text into actionable insights.
• Own full lifecycle: capture business needs, feasibility, models, data pipelines, deployment and monitoring.
• Set up rigorous evaluation including experiment design, impact measures, guardrails and validation.
• Develop dashboards and feedback loops for business users to refine predictions; apply MLOps best practices.
• Translate technical results into clear business insights and mentor junior data scientists.

Skills

Python & data science

Customer journey modeling

Experiment design

Statistical methods

LLMs for text classification

English fluency

French or Dutch fluency

ML engineering practices

Education

Master's degree in quantitative field

Tools

Git

Bash

SQL

scikit-learn

PyTorch

TensorFlow

MLflow

Streamlit

Job description

Senior Data Scientist | Brussels

At Exsolvæ, our consultants carry the title of Solver, and it's a title you earn. We take the development of every Solver seriously, each one belongs to a Core Domain, works with a Leader who actually follows their progress, and presents their work in Cerebro sessions to colleagues who know the field as well as they do. It's a demanding place, on purpose.

The Data Science & AI Core Domain serves some of the biggest names across finance, retail, automotive, etc.

For this mission, you'll join the marketing data science team of a leading company in Belgium, building responsible AI models that make campaigns more relevant for millions of customers.

That's the work we're hiring for.

Your role, on mission

• Build responsible AI models that make marketing campaigns more relevant and impactful, from target group selection to customer journey driven campaigns (next best action)
• Use LLMs and fine-tuned models to turn large volumes of unstructured text, such as client interaction notes and web analytics data, into insights on products discussed, customer intent and feedback
• Own the full lifecycle: capturing business needs, assessing feasibility, building models and data pipelines, deploying and monitoring them in production
• Set up rigorous evaluation: experiment design, impact measurement, guardrails and validation of LLM-driven predictions
• Build feedback loops and dashboards that let business users correct predictions and keep models learning
• Bring MLOps best practices to the team (MLflow, reproducible models and datasets)
• Translate technical results into clear, actionable insights for business owners, and guide junior data scientists along the way

Your role, within the community

• Share what you learn: Cerebro sessions, co-built playbooks, code reviews between Solvers
• Mentor peers and be mentored: seniors who enjoy passing on what they know do well here
• Help shape where the Core Domain goes next

Must-haves

• Master's degree in a quantitative field (statistics, mathematics, computer science); other academic backgrounds with substantial data science experience are welcome
• Senior profile: minimum 5 years of relevant experience in data science
• Expert Python and its data science ecosystem (scikit-learn, PyTorch, TensorFlow), with solid engineering practices (git, bash, SQL)
• Expertise in customer journey modeling
• Solid understanding of statistical methods, experiment design and machine learning, both traditional and deep learning
• Proven expertise using LLMs for text classification, including interpretability, guardrails and validation of LLM-driven predictions
• Fluent English, plus fluent French or Dutch
• Based in Belgium and available on-site in Brussels 50% of the time
• A genuine desire to be part of a community: you share what you know and you show up for the collective moments

Strong assets

• Incremental learning and closed feedback loops
• Uplift modeling
• Marketing Mix Modeling and optimization under constraints
• MLOps: MLflow, model monitoring and delivery pipelines
• SAS, Streamlit
• Financial services background

Joining Exsolvæ, concretely

• A community before anything else: a Core Domain led by a Leader who follows your development, Cerebro sessions where Solvers present and learn, playbooks built together
• A Knowledge & Networking budget to keep learning and stay plugged into the ecosystem (emerging AI topics, MLOps, AI governance)
• A followed career path with a dedicated Manager, regular check-ins, an evolution committee that formalises your progression and issues recommendations
• Long-run missions at leading companies, in production
• A permanent employee contract, with a competitive package