A public social security organisation in Belgium maintains a mix of legacy mainframe systems and newer service layers; this role exists to keep COBOL applications stable while contributing to selective modernisation. You will work on COBOL maintenance and development, translating functional analyses into technical specifications and using Git/GitHub for version control in an Agile delivery model.
The mission
The team supports core social security applications that run on a legacy mainframe COBOL estate and integrate with Java and .NET services. Work covers defect repair, root cause analysis, unit and integration testing, and incremental modernisation where functionality is refactored or exposed via APIs. The environment uses SQL databases, Java Spring Boot and .NET/Angular front ends for surrounding services.
You will operate day to day inside a small cross-functional team (around 6-10 developers and analysts) that delivers in Agile sprints. Your responsibilities include converting business or functional analyses into technical specifications, implementing and testing COBOL programs, coordinating validation tests with business users, and updating documentation. You will also share knowledge, contribute to code reviews on GitHub, and apply AI-assisted tools where they speed up analysis and testing.
Your responsibilities
- Translate functional analyses into clear technical specifications and deliver tested COBOL code that meets those specifications
- Fix defects and perform root cause analysis to reduce recurrence and improve system stability
- Execute and automate unit and integration tests, and support business users during validation cycles
- Integrate COBOL components with surrounding services, coordinating with Java, .NET and Angular teams
- Maintain and improve source control practices using Git and GitHub, including code reviews and branch management
- Produce and maintain concise technical documentation and share lessons learned with the team
Your profile
Essential skills
- Strong track record as a senior COBOL developer, with several years of recent hands-on COBOL maintenance and development experience
- Proven experience handling legacy mainframe code, defect management and root cause analysis
- Comfortable translating functional requirements into technical specifications and test plans
- Practical experience with Git and GitHub for version control and code review
- Working knowledge of SQL, and familiarity with Java (Spring Boot), .NET and Angular in an integrated landscape
- Experience working in Agile teams and using AI-assisted tools to support analysis or testing
Languages
- French, C2
- Dutch, C2
- English, B2
Education
- Bachelor degree in programming, computer science or equivalent professional experience
In addition to your CV, please include a short, concrete example from your experience describing the use of conditional compilation in COBOL. An insufficient answer to this question will disqualify the application.