Mendix Modernization Legacy Application Developer

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Intro

RELYzIT Talent is seeking a Mendix Modernization Legacy Application Developer for a high-impact freelance mission in Brussels, Belgium. Join a multidisciplinary team to help our client transform a complex, business-critical legacy application into a future-proof, low-code solution. This is your opportunity to shape the digital backbone of a major organization, leveraging cutting-edge automation, AI, and model-driven development to deliver lasting value.

Why This Role Matters

Our client’s legacy application, built in Adobe ColdFusion and spanning over 150,000 lines of code across 20 modules, is the engine behind essential business processes—file management, data processing, and reporting. Modernizing this system is not just a technical upgrade; it’s a mission-critical transformation that will drive efficiency, scalability, and innovation for years to come. Your expertise will directly impact the success of this migration, ensuring business continuity and unlocking new capabilities through a robust, low-code Mendix platform.

What You’ll Be Doing

• Analyze and map existing business processes, functionalities, and application architecture to inform the modernization strategy.
• Validate outputs and ensure alignment with business objectives throughout the migration lifecycle.
• Translate complex business needs into actionable user stories and maintain a prioritized backlog.
• Prepare and facilitate workshops with stakeholders to capture requirements and drive consensus.
• Produce clear, comprehensive functional documentation to support development and migration activities.
• Leverage AI-driven code analysis and model-driven methodologies to maximize reuse of existing logic and accelerate migration.
• Collaborate with technical and business teams to ensure seamless integration and process optimization.
• Support the delivery of standalone, value-driven project phases, each capable of independent operation.
• Champion quality, efficiency, and innovation at every stage of the modernization journey.

What We’re Looking For

• Proven expertise in business and functional analysis, with a track record of delivering impactful solutions in complex environments.
• Ownership mindset: you take initiative, drive outcomes, and thrive in multidisciplinary teams.
• Strong problem-solving skills, with the ability to valorize and reuse existing assets for maximum migration efficiency.
• Experience in facilitating workshops, gathering requirements, and translating them into actionable deliverables.
• Commitment to quality, transparency, and continuous improvement.

Technical Skills

• Artificial Intelligence (Junior): Familiarity with AI-driven code analysis and automation tools.
• Business Analysis / Functional Analysis (Expert): Deep understanding of business process mapping, requirements gathering, and documentation.
• Communication Skills (Expert): Ability to engage stakeholders, lead workshops, and produce clear documentation.
• Mendix Development (Confirmed): Hands-on experience with Mendix or similar low-code platforms.
• Migration of Applications, Processes, and Data (Confirmed): Demonstrated success in migrating legacy systems to modern platforms.
• Process Optimization (Expert): Proven ability to streamline and enhance business processes.
• UML & BPMN (Expert): Advanced skills in modeling and documenting business processes and system architectures.

Language Proficiency

• Professional proficiency in English is required.
• Knowledge of French or Dutch is a strong advantage.

Other Requirements

• All relevant certificates and supporting documents must be attached to your CV and will be validated as part of the selection process.
• Experience with Agile/Scrum methodologies is highly valued.
• Partial remote work is possible; on-site presence in Brussels required as per project needs.
• Demonstrable experience applying innovative migration methodologies in completed or ongoing projects.
• This is a freelance position, with project phases ordered and delivered independently. Duration and start date are subject to budget approval.

Ready to build the future with RELYzIT Talent? Upload your CV and supporting documents now to join our elite builder community and make your mark on a mission that matters.