Mainframe Developer

KEYES

Herstal, Liège, Belgium Posted October 23, 2026

Check how well your resume matches this job

Remote Full-time Senior
Job Description

Are you looking to take the next step in your career and grow within one of Belgium’s leading IT companies?

Join KEYES as a Mainframe Developer!

KEYES delivers integrated digital solutions through a unique ecosystem of seven areas of expertise: Infrastructure & Cloud, Cybersecurity, Data & AI, Business Software, Mainframe, Advisory and Staffing. Together, they enable organisations of all sizes to transform, perform and growresponsibly.

At KEYES, talents work across domains, contribute to impactful projects and help build the digital future.

Find out more: www.keyes.eu

YOUR MISSION

  • You will contribute to application development projects in a mainframe environment as part of our project teams

  • You will carry out technical analysis, development, and unit and/or integration testing of programs and applications in both project-based and maintenance environments

  • Based on functional specifications, you will develop applications in an efficient, testable, and maintainable manner

  • You will develop applications on IBM mainframe systems

  • You will build robust and scalable back-end systems capable of handling high volumes of daily requests

  • You will proactively challenge existing approaches and propose alternative solutions through collaboration and knowledge-sharing with colleagues

  • You will maintain existing applications, implement changes where necessary, and troubleshoot production incidents

OUR OFFER

  • Complete salary package

  • A function rich in responsibilities and challenges

  • A team of enthusiastic, professional colleagues in which there is an excellent atmosphere and where expertise is shared

  • Tools and infrastructure that are consistently at the forefront of innovation

  • Personalized career support to help you with your development

  • Many training opportunities and certifications

  • A company with a friendly working atmosphere which is dynamic and oriented towards innovation

  • Fun times – a food truck, barbecue, after-work events, family day!

VOTRE PROFIL

  • You have at least 5 years of experience in application development using PL/I

  • Experience in the insurance sector (life or non-life) is considered a strong advantage

  • Technical skills: PL/I, COBOL, DL/I, DB2, IMS, TSO, JCL, JavaScript, Angular, HTML, Java…

  • You have strong communication skills and are able to work effectively as part of a team

  • You are fluent in French and English; knowledge of Dutch is a significant asset

Do you recognise yourself in this description ? 

Do you want to learn more ?  

Apply now! You will be contacted shortly 

What if the mission isn’t an exact match for you ?  

Let’s stay in touch ! Sign up, and we may contact you for other future opportunities : https://keyescareers.eu/o/spontaneous-application

OUR RECRUITMENT PROCESS is efficient, transparent and fair :  

#LI-FC1

Required Skills
cybersecurity testing collaboration troubleshooting JavaScript Angular HTML Java communication French English Dutch recruiting
How to apply

You apply on KEYES’s own careers site. No account needed.

Apply on company site
How well do you match?

Upload your resume and ARes scores it against this job in a few seconds. No account needed.

Your resume is read to calculate the match and then deleted. Nothing is saved.

Already have access? Sign in
About KEYES

See every open role at KEYES on ARes.

More Jobs at KEYES
Share This Job