Senior Expert Software Engineer

• Locations Belgium Poland France United Kingdom Netherlands

Division:
Group Business Solutions (GBS)

Your career opportunity

Join our Group Business Solutions (GBS) division, where we design and sustain IT solutions for financial market securities. Be part of a dynamic, collaborative team in a fast-evolving environment, shaping the future of financial technology.

Ready to make an impact?

We’re seeking a skilled and proactive Senior Expert Engineer to strengthen our solutions and drive impactful improvements. You’ll collaborate across teams, provide guidance, and lead key initiatives in an innovative, growth‑oriented environment that ensures strong alignment between technology and business needs

• Drive the design, architecture, and implementation of technical solutions, owning complex features and collaborating with senior developers and cross‑functional teams to deliver robust, scalable systems. Participates in the detailed design process, defining system scope and objectives for assigned projects. Contribute to supervising and validating the development process. Develops or modifies procedures to solve complex problems, considering system capacity, performance constraints, and desired outcomes.
  
  Support testing teams during the various testing phases of projects and occasionally contribute to application testing activities
• Provide strong mentorship and technical leadership to mid-level engineers, guiding them through complex problem‑solving, contributing to the growth and technical maturity of the team.
• Guide ideation workshops by setting the tone, bringing together complex insights, and helping teams shape high‑impact ideas to improve product functionality. Drive the definition, estimation, and validation of complex technical requirements for multi‑team features. Anticipate dependencies, improve planning accuracy, and guide teams toward predictable, high‑quality delivery through strong technical judgment and cross‑team collaboration.
• Maintain production stability by independently leading technical investigations, delivering durable fixes. Proactively identify and resolve systemic issues to strengthen operational resilience. Support production activities (including off-hours)
• Promote and refine best practices and coding standards within the team, applying a strong understanding of system requirements and existing business processes. Contribute to and help lead continuous improvement initiatives that enhance code quality and overall engineering effectiveness.

Work outside of business hours is sometimes required as launches in production are generally carried out after 5PM or on Saturday or Sunday as well as watch duty during nights and weekends.

What you need to have to succeed in this role:

• Solid experience as a software engineer (at least 10 years).
• Deep understanding of software related system architectures and designs.
• Solid knowledge of solution development and design principles.
• Demonstrates strong ability to analyze and interpret business requirements, anticipate technical implications, and guide the creation of well‑designed, scalable technical solutions.
• Demonstrates continued technical growth, effective cross‑functional collaboration, and growing ownership of cloud migration, AI integration, automation, Infrastructure as Code, CI/CD pipelines, engineering best practices, and collaborative delivery.
• Solid coaching and mentoring skills
• Strong command of English, both spoken and written.
• Experience on major projects and complex / large-scale systems
• Hands‑on experience with tools such as:
• IBM Mainframe: PL/I, DB2, MQ, CICS
• Java or .Net development stacks as well as a good command of APIs, Integration mechanisms and Data technologies.
• Experience with event‑driven architecture principles and its implementation with Kafka
• Experience with private cloud technologies (Azure).
• Nice to have:
  • Experience with Linux Java development stack & IntelliJ IDEA, Eclipse, JDK, Javac/Java commands, Maven, Gradle, IDE environments, JUnit, Git, Docker, CI/CD pipelines (Jenkins, Git Hub Actions), Prometheus, Grafana, Open Telemetry, VisualVM, JFR, Kubernetes, Azure Cloud, AWS, GCP, VPC/VNet, CLI, Visual Studio,…