Senior Mendix Developer

Callisto Web Solutions B.V.; Amsterdam; On-site; EUR 90,000 - 130,000; Full time

Job summary

Callisto Web Solutions B.V. is seeking a Senior Mendix Developer to lead the design, development, and delivery of scalable enterprise applications.

You will provide technical leadership, influence solution architecture, and collaborate with stakeholders to deliver secure, high-performing solutions. Responsibilities include mentoring Mendix developers, driving architecture and design, and managing complex integrations via REST/SOAP APIs while adhering to governance and security standards.

Qualifications

• 5+ years of hands-on Mendix development experience.
• Proven experience with production-critical, enterprise-scale applications.
• Strong understanding of Mendix architecture and best practices.
• Experience with CI/CD pipelines, governance, and security.
• Strong experience with REST, SOAP APIs, and system integrations.
• Excellent problem-solving and analytical skills.
• Strong communication skills with business and technical stakeholders.

Responsibilities

• Provide technical leadership and mentorship to Mendix developers.
• Drive solution architecture, design, and ensure scalability, performance, maintainability, and security.
• Collaborate with business stakeholders, PMs, POs, and Scrum teams.
• Design and manage complex integrations via REST, SOAP, APIs.
• Contribute to technical standards, best practices, and governance.
• Support continuous improvement of development processes and tooling.
• Ensure enterprise requirements for security, reliability, and performance.

Skills

Mendix development

Enterprise-scale apps

CI/CD pipelines

REST/SOAP APIs

Problem solving

Stakeholder communication

Education

Mendix Advanced or Expert Certification

Job description

We are looking for an experienced Senior Mendix Developer to join our team and play a key role in designing, developing, and delivering scalable enterprise applications.

In this role, you will provide technical leadership, contribute to solution architecture, and work closely with business and technical stakeholders to deliver secure, high-performing solutions.

Key Responsibilities

• Provide technical leadership and mentorship to junior and mid-level Mendix developers.
• Drive solution architecture and technical design, ensuring scalability, performance, maintainability, and security.
• Collaborate closely with business stakeholders, project managers, product owners, and Scrum teams.
• Design and manage complex integrations using REST, SOAP, APIs, and other integration technologies.
• Contribute to technical standards, development best practices, and governance.
• Support the continuous improvement of development processes, tooling, and application quality.
• Ensure solutions meet enterprise requirements for security, reliability, and performance.

Requirements

• 5+ years of hands-on experience in Mendix development.
• Proven experience working with production-critical and enterprise-scale applications.
• Strong understanding of Mendix architecture, application development, and best practices.
• Experience with CI/CD pipelines, application governance, and security.
• Strong experience with REST, SOAP, APIs, and system integrations.
• Excellent problem-solving and analytical skills.
• Strong communication skills and the ability to collaborate effectively with both technical and business stakeholders.
• Mendix Advanced or Expert Certification is preferred.