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).