ESB Consultant - Integration Engineer

Joining KEYES Means Giving Purpose to Your Talent Are you looking for an environment where technology is not an end in itself, but a lever for building a sustainable future? At KEYES , we are not only looking for technical expertise; we are looking for people who share our values. Would you like to advance your career and grow within one of Belgium’s leading IT companies? Join KEYES as an ESB Developer (JAVA) - Integration Developer! KEYES supports private and public organizations across Belgium and Europe in their digital transformation by combining business expertise, technological excellence, and a long-term vision. We support large enterprises, public sector organizations, healthcare providers, and SMEs in addressing their digital challenges through Infrastructure & Cloud Solutions, Cybersecurity Solutions, Business Software Solutions, Mainframe Solutions, Data & AI Solutions, Advisory Solutions, and Staffing Solutions. More information: www.keyes.eu Your Mission As a major player in information systems integration, KEYES is looking for an ESB Developer who can work either as a permanent employee or as a freelancer. The position is part of a Java-based environment where application integration flows are orchestrated using an Enterprise Service Bus (ESB) such as MuleSoft, IBM Integration Bus, Red Hat Fuse , or equivalent solutions. The successful candidate will demonstrate a high degree of autonomy and strong analytical skills to design, develop, and optimize integration solutions within complex business and technical environments. Your Responsibilities Functional and Technical Analysis: Gather business requirements, assess existing architectures, and propose suitable integration solutions. ESB Flow Design: Design message routes, define routing rules, data transformations (XML, JSON, CSV), and governance policies. Java Development: Implement integration components (adapters, transformers, services) in Java while adhering to code quality and security best practices. ESB Implementation and Configuration: Configure connectors (HTTP, JMS, SOAP/REST, AMQP), manage endpoints, queues and topics, and ensure flow monitoring. Performance Optimization: Analyze bottlenecks and fine-tune threading, pooling, and caching to meet latency and throughput requirements. Testing and Validation: Design unit and integration test suites, automate CI/CD pipelines (Jenkins, GitLab CI), and validate compliance with functional requirements. Support and Continuous Improvement: Provide production support, troubleshoot incidents, propose continuous improvements, and document delivered solutions. Technology Watch: Stay up to date with ESB platforms, integration standards, and DevOps practices to enhance internal methodologies and frameworks. #LI-CV1 OUR OFFER A role rich in responsibilities and challenges . The opportunity to join a Top Employer certified for several consecutive years, reflecting the quality of our HR practices and our commitment to providing an optimal work environment and employee well-being. A team of enthusiastic and professional colleagues in a friendly work atmosphere where knowledge and expertise are actively shared . A dynamic company focused on innovation . Personalized career support tailored to your expectations and ambitions, with opportunities for growth through our various development plans. Continuous learning through numerous training and certification opportunities . Access to an innovative e-learning platform offering unlimited access to more than 25,000 hard and soft skills training resources from Edflex and Udemy . The possibility of hybrid working : depending on your assignment, you may work from our offices in the Liège region , Brussels , or Heverlee . You can also work remotely up to three days per week . A comprehensive compensation package . As part of our commitment to reducing our environmental impact, KEYES has transitioned to an electrified company vehicle fleet . Fun moments including food trucks, barbecues, after-work events, family days, and more. Higher education degree with a specialization in application development , or equivalent through professional experience. Experience: Minimum 4 years of proven experience in ESB integration development, including significant experience on Java-based projects. Technical skills: Strong proficiency in Java (JDK 8 or higher) , in-depth knowledge of at least one commercial or open-source ESB platform (such as MuleSoft, IBM Integration Bus, Red Hat Fuse, WSO2, TIBCO, Dell Boomi , etc.), and solid understanding of HTTP/HTTPS, JMS, SOAP/REST protocols and XML/JSON formats. Analysis and problem-solving: Ability to understand complex business processes, model integration scenarios, and propose robust technical solutions. Autonomy: Ability to work independently, manage priorities and schedules, and make sound technical decisions. Methodologies: Experience working in Agile/Scrum environments, familiarity with DevOps practices (CI/CD, Docker, Kubernetes), and proficiency with version control tools such as Git . Communication: Excellent written and verbal communication skills in French (and a very good command of English ) to collaborate effectively with both business and technical teams. Employment status: Open to candidates seeking a permanent employment contract or working as independent contractors (freelancers/consultants) . Fluency in French and a good command of English are essential. Knowledge of Dutch is considered an asset. If you are ready to take on this challenge, thrive in a stimulating environment, and contribute to innovative projects, we would be delighted to receive your application! Join KEYES and become part of a rewarding adventure! OUR RECRUITMENT PROCESS Our recruitment process is designed to be efficient, transparent, and fair: