We are looking for a Senior Data Engineer SQL for one of our clients based in Luxembourg Freelance or permanent contract via payrolling company Strong expertise in advanced SQL development and enterprise data modelling (Data Vault, dimensional, 3NF) Fluent English is mandatory, German or French is a plus Your responsibilities SQL development & Data modelling: You will design and optimize complex SQL transformations to support analytics, reporting, and regulatory requirements You will contribute to and enhance existing enterprise data models using structured methodologies You will ensure high-performance, maintainable SQL aligned with modelling standards You will implement robust data quality checks, validation rules, and SQL testing frameworks You will document data lineage, metadata, and architecture for transparency and governance You will help reduce architectural debt and maintain a consistent data ecosystem Data pipelines & integration engineering: You will build and maintain SQL-centric ETL/ELT pipelines You will leverage Python to automate workflows and integrate APIs when needed You will implement batch, incremental, and near real-time ingestion patterns You will ensure strong monitoring, observability, and reliability of data pipelines Business Intelligence enablement: You will structure SQL datasets optimized for BI consumption You will support data preparation, extraction logic, and backend performance You will assist BI teams with troubleshooting, prototyping, and governance topics Cross functional collaboration: You will collaborate with Finance, risk, compliance, and business teams to translate requirements into data solutions You will align closely with data architects to ensure consistency in modelling approaches You will troubleshoot across data ingestion, modelling, and operational layers You will contribute to platform evolution and continuous engineering improvements You will communicate effectively with both technical and non-technical stakeholders Data platform & operational excellence: You will work with infrastructure teams to ensure reliable production operations You will apply best engineering practices including Version Control, documentation, testing, and code quality Profile You are highly proficient in SQL, including complex queries, tuning, and optimization You are experienced with enterprise data models such as Data Vault, dimensional models, SCD, or 3NF You are comfortable building scalable SQL-based transformations You are familiar with Python for automation and workflow enhancements You are experienced with BI tools such as Tableau or Power BI (considered an advantage) You are knowledgeable in financial services or regulated environments (a strong asset) You are committed to delivering reliable, maintainable, and well-tested data solutions You are quality-driven with a focus on monitoring, automation, and reliability You are proactive, solution-oriented, and engaged across the full data lifecycle You are able to refine requirements and collaborate effectively with diverse stakeholders You hold a Bachelor's or Master's degree in a relevant field You have at least 5 years of experience in data engineering or SQL-heavy backend roles You are familiar with banking or financial environments You may have exposure to core banking platforms such as Temenos (considered a plus) Hays plc est l'un des principaux groupes mondiaux de recrutement de professionnels. Hays est l'expert du recrutement de personnes qualifiées, professionnelles et compétentes dans le monde entier. Hays est le leader du marché au Royaume-Uni et en Asie-Pacifique et également l'un des leaders du marché en Europe continentale et en Amérique latine. Hays intervient pour le compte de milliers d'entreprises des secteurs privé et public, sur des postes en CDI, CDD, Travail Temporaire et Contracting. Hays France & Luxembourg compte aujourd'hui plus de 650 salariés répartis au sein de 22 bureaux (Aix-en-Provence, Amiens, Biarritz, Bordeaux, Clermont-Ferrand, Dijon, Grenoble, La Rochelle, Lille, Lyon, Montpellier, Nancy, Nantes, Nice, Paris, Reims, Rennes, Rouen, Strasbourg, Toulouse, Tours et au Luxembourg) couvrant 25 secteurs d'activité.