Mendix developer

Phoenix Technologies; Brussel Hoofdstad; On-site; EUR 60,000 - 90,000; Full time

Job summary

Phoenix Technologies is seeking an experienced Mendix Developer to design, build, and maintain business applications on the Mendix low-code platform within the GSC environment. You will work in agile teams with analysts, UX/UI designers, testers and project managers to keep applications consistent, maintainable, and reusable across the Mendix portfolio.

The role requires hands-on Mendix expertise (3+ years) and a strong background in Java/JavaScript for custom actions.

Qualifications

• 5+ years in IT development with hands-on Mendix
• Proven delivery of Mendix apps into production with enterprise integrations
• Experience with Mendix 10 or later, on-premises or private cloud

Responsibilities

• Translate user stories and requirements into Mendix apps (domain models, flows, pages, security roles).
• Build integrations with internal/external systems via APIs and connectors, implement SSO (SAML/OIDC).
• Develop reusable modules/widgets in line with GSC standards and contribute to the shared library.
• Apply secure-by-design practices and RBAC; ensure data protection requirements.
• Create accessible interfaces meeting WCAG 2.1 AA.
• Write tests and participate in code reviews; manage technical debt with Mendix tools.
• Support deployments, releases, and production maintenance.
• Produce and maintain technical documentation.

Skills

Mendix

Java

JavaScript

Scrum

System integration

Education

Mendix Advanced Developer certification

Mendix 10+ experience

Tools

Mendix Studio Pro

Job description

Role summary

Designs, builds and maintains business applications on the Mendix low-code platform within the GSC's environment. Work in agile, multidisciplinary teams alongside business analysts, UX/UI designers, testers and project managers, and apply the GSC's shared development principles so that applications stay consistent, maintainable and reusable across the Mendix portfolio.

Main tasks

• Translate user stories and business requirements into working Mendix applications (domain models, flows, pages, security roles).

• Build integrations with internal and external systems via APIs and database connectors, and implement single sign-on (SAML/OIDC).

• Develop reusable modules, widgets and components in line with GSC standards, and contribute to a shared component library.

• Apply secure-by-design practices, role-based access control and data protection requirements.

• Build accessible interfaces that meet WCAG 2.1 AA.

• Write unit and automated tests, take part in code reviews, and use the Mendix Quality Add-ons or equivalent to keep technical debt under control.

• Support deployment, release management and third-level maintenance of applications in production.

• Produce and maintain technical documentation.

Required qualifications and experience

• At least 5 years of IT development experience, including at least 3 years hands-on with Mendix.

• Mendix Advanced Developer certification (minimum).

• Proven delivery of at least two Mendix applications into production, including integration with enterprise systems.

• Experience with Mendix 10 or later, on-premises or private cloud deployment.

• Working knowledge of Java and JavaScript for custom actions and widgets.

• Experience working in Scrum or similar agile frameworks.

Assets

• Mendix Expert certification.

• Experience in an EU institution or public administration.

• Experience with Mendix AI capabilities (e.g. GenAI connectors, Maia).

Languages

• English at C1 level. French is an asset.