Senior Fullstack Software Engineer (.NET & React)

About the role

Deloitte Luxembourg's Digital Factory is looking for a Senior Fullstack Software Engineer (.NET & React) to join a multidisciplinary team of about 85 technology professionals and financial domain experts. The team builds data-driven digital solutions for banking, investment funds and asset management in an Agile environment. The role is on-site and full-time, and the engineer owns solutions end-to-end, shapes engineering practices and helps grow the team.

Key responsibilities

• Architect, develop and own full-stack applications from concept to production, focusing on scalability, resilience and maintainability in a financial services context
• Design and implement high-performance, data-intensive APIs, workflows and integrations using C#/.NET and SQL Server
• Apply architectural patterns such as clean architecture, CQRS and event-driven design
• Build scalable React user interfaces with strong component architecture and state management
• Define and enforce engineering standards: code reviews, unit, integration and E2E testing, and CI/CD pipeline ownership
• Own non-functional requirements including performance, security and observability, and proactively address technical debt
• Mentor junior and mid-level engineers through pairing, feedback and knowledge sharing
• Lead technical discussions, turn business requirements into technical designs, and contribute to hiring via technical interviews
• Communicate delivery risks, scope and progress to the team and project leads
• Champion Agile practices in sprint ceremonies and propose improvements to team processes and tooling

Required profile

• University degree in Computer Science, Software Engineering or a related field
• Fluent English; French is an asset
• 4 to 8 years of hands-on software development experience, with a track record of complex, production-grade full-stack applications; financial sector experience is a plus
• Technical leadership: able to lead design discussions and make reasoned decisions under ambiguity
• Mentorship mindset and ownership: drives delivery, raises risks early and takes pride in shipped work

Required skills

• C#/.NET (Core)
• SQL and relational databases
• React development
• API design and CI/CD definition
• Nice to have: cloud platforms, containerization, event-driven architecture, AI integration

What we offer

• Work on data-intensive applications used by major financial institutions, with a learning budget, internal tech talks and access to a global knowledge network
• A clear path toward Lead Engineer and Architect roles
• Flexible hybrid working arrangements
• International projects with teams across Deloitte's global network, based in Luxembourg