Senior Fullstack Software Engineer (.NET & React)

Date: 31 Jul 2026

Location:

Luxembourg, LU

Company: Deloitte Luxembourg

Job Function: Technology & Cyber Security

Seniority: Senior levels

Contract Type: Open-term

On site

Full time

Your future team

Join our Digital Factory at Deloitte Luxembourg — a multidisciplinary team of ~85 technology professionals and financial domain experts working together to build high-impact digital solutions for the financial sector. We develop modern, data-driven products serving clients in banking, investment funds, and asset management, in a collaborative Agile environment with a strong focus on engineering quality and continuous improvement.

As a Senior Engineer, you will be a key technical pillar of the team – owning solutions end-to-end, shaping our engineering practices, and helping grow the people around you.

Your advantages of joining us

Work that has real impact
Build and architect data-intensive applications used by major financial institutions, leveraging modern engineering standards and AI-enabled tooling. Your decisions will directly influence product quality and client outcomes.
Technical leadership & career growth
Take ownership of architectural decisions and technical direction, with a clear path toward Lead Engineer and Architect roles. Benefit from a dedicated learning budget, internal tech talks, and access to Deloitte's global knowledge network.
Global reach, local roots
Contribute to international projects and collaborate with diverse teams across Deloitte's global network, all while being anchored in Luxembourg – one of Europe's leading financial centers.
Flexible, inclusive culture
We trust our people. Enjoy flexible hybrid working arrangements, a culture where your voice genuinely shapes how we work, and a team that values both performance and wellbeing.
A team that builds together
Work side by side with financial experts, product owners, and fellow engineers in a startup-minded environment within a globally recognized firm.

How you'll contribute to our success

Engineering & Architecture

• Architect, develop, and own robust full-stack applications from concept to production, with a strong focus on scalability, resilience, and maintainability in a financial services context
• Design and implement high-performance, data-intensive APIs, processing workflows, and integrations using C#/.NET and SQL Server
• Define and apply sound architectural patterns (e.g., clean architecture, CQRS, event-driven design) appropriate to the problem at hand
• Build scalable, performant user interfaces with React, applying strong component architecture and state management best practices

Quality & Engineering Standards

• Define, promote, and enforce engineering standards across the team: code reviews, testing strategies (unit, integration, E2E), and CI/CD pipeline ownership
• Own non-functional requirements including performance, security, and observability
• Proactively identify technical debt and drive pragmatic remediation plans

Leadership & Collaboration

• Act as a technical mentor for junior and mid-level engineers, supporting their growth through pairing, feedback, and knowledge sharing
• Lead technical discussions and drive consensus across engineers and business stakeholders
• Translate complex business requirements into clear, actionable technical designs
• Contribute to hiring by participating in technical interviews and candidate assessments
• Communicate delivery risks, scope, and progress transparently to the team and project leads

Agile & Continuous Improvement

• Champion Agile best practices within the team, contributing to sprint ceremonies with a focus on sustainable delivery and continuous improvement
• Propose and implement improvements to team processes, tooling, and ways of working

Your skills

University degree in Computer Science, Software Engineering, or another relevant field.
Fluent English is required. French is considered an asset.
5 to 10 years of hands-on experience in software development, with a proven track record of delivering complex, production-grade full-stack applications. Experience in the financial sector is a plus.
Technical skills : C#/.NET (Core), SQL/relational databases, React development, API design, CI/CD definition.Nice-to-have: Cloud platforms, Containerization, Event-driven architecture, AI integration.
Technical leadership: Ability to lead design discussions, make well-reasoned decisions under ambiguity, and bring others along
Mentorship mindset: Genuine interest in growing the people around you through coaching, feedback, and knowledge sharing
Ownership: You drive delivery, raise risks early, unblock your team, and take pride in what you ship

Interested? Please submit your resume in English

Get to know more about Deloitte on our LinkedIn page (#DeloitteLU), Instagram page, YouTube page or website.

With more than 2,600 employees and 98 nationalities, Deloitte Luxembourg is one of the Grand Duchy's largest, strongest and oldest professional services firms. For more than 75 years, our talented teams have been serving clients in various industries delivering high added-value offerings to national and international clients in audit and assurance, consulting, financial advisory, risk advisory, tax, and related services. Deloitte Luxembourg is part of the global Deloitte network.

Deloitte provides leading professional services to nearly 90% of the Fortune Global 500® and thousands of private companies. Our people deliver measurable and lasting results that help reinforce public trust in capital markets and enable clients to transform and thrive. Building on its 180+-year history, Deloitte spans more than 150 countries and territories. Learn how Deloitte’s over 470,000 people worldwide work together every day to make an impact that matters at www.deloitte.com.

Requisition ID: 14077