Data Scientist - Generative AI / LLM

We are looking for a freelance Data Scientist with strong Generative AI experience to join a leading bank in Brussels. You will work on concrete GenAI use cases: LLM-powered assistants, RAG over internal data and agentic workflows that support business users.

The role is hands-on: designing, building and industrialising GenAI solutions together with an existing data/GenAI team.

What you will do

Design and implement LLM applications (question-answering, assistants, document understanding, decision support).

Build and optimise RAG pipelines (data ingestion, chunking, vector search, evaluation).

Develop agentic workflows using LangChain / LangGraph or similar (tools, multi-step flows, orchestration).

Work closely with business stakeholders to understand use cases and translate them into GenAI solutions.

Explain to non-technical users how to get the best results from prompts and GenAI tools.

Contribute to good practices around LLMOps (monitoring, evaluation, cost and performance optimisation).

Must-have experience

2–5 years in Data Science / ML / AI.

Strong Python and deep learning background (transformers or similar).

Hands-on experience with Generative AI and LLMs (GPT, open-source models, etc.) in real projects.

Practical experience with LangChain or similar framework for building LLM applications.

Solid experience with RAG and vector databases.

Exposure to agentic workflows (agents, tools, multi-step reasoning) – or strong interest plus first concrete projects.

Good understanding of prompt engineering and ability to explain it clearly to business users.

You speak English fluently and can follow meetings in French or Dutch (you can respond in English).

Able to work 2–3 days per week onsite in Brussels (50% onsite).

Nice to have

Experience in banking, insurance or other regulated industries.

Experience with Azure or another major cloud platform for data / AI.

Experience with MLOps / LLMOps (MLflow, CI/CD, monitoring, evaluation).

Contract details

Freelance / contract position.

Long-term mission (12 months+, extensions likely).