API/SOA Developer (Freelance)

API/SOA Developer (Freelance) I'm applying now !! Location: Brussels, Belgium (Hybrid: 2-3 days remote per week) Contract Type: Freelance (Prestation de services) Levels & Experience Required: Junior (1 year exp.) | Medior (3 years exp.) | Senior (10 years exp.) Language Requirements: Fluent in English (3/4) OR fluent in Dutch/French (3/4) About Smile: Why Join Us? 😊 Passionate about tech, digital, and innovation? Join the 1,800 employees at Smile , the European leader in open-source integration, spread across 20 agencies in 9 countries. Collaborative spirit and knowledge sharing are at the heart of our DNA. Our experts push the boundaries of open source every day to build a smarter, more efficient, and more responsible digital world. Here, we don't just follow trends, we create them! 🌟 Join Smile in Brussels and take part in projects that truly matter! 🏆 Peer-to-Peer Management: Our proximity management by peers fosters dialogue and the implementation of a tailored career path. Continuous Learning: Because the digital sector is in constant motion, Smile is committed to making you an expert in your field, thanks to a comprehensive training offer: access to an e-learning platform, financing of certifications, and robust knowledge-sharing tools. Vibrant Community: Your year will be animated by group and agency events: annual convention, participation in trade fairs, summer party, and plenty of formal & informal afterworks. Role Overview On behalf of our fast-growing division, we are looking for API/SOA Developers at different seniority levels ( Junior, Medior, and Senior ) to join our consultant pool in Brussels. In this role, you will be key to developing, securing, and maintaining modern API and Service-Oriented Architectures (SOA). Working on behalf of our premier client in Brussels, you will build clean, secure integrations and play a central part in bridging legacy systems with modern cloud infrastructure. Key Responsibilities Depending on your level of seniority, your responsibilities will include: API & SOA Development: Developing high-quality backend APIs and services using Java within SOA, REST, and event-driven architectures. API Management & Integration: Implementing and configuring integration points across enterprise platforms such as Axway, Apigee, or WSO2 . Security & Vulnerability Management: Incorporating robust security standards (OAuth2, JWT, SOAP security) and securing code using tools like Snyk and PKI (Public Key Infrastructure) . Cloud & CI/CD Pipelines: Deploying and managing applications within Public Cloud environments, actively utilizing Git and automation-driven CI/CD pipelines. Testing & Quality Assurance: Conducting thorough automated testing of web services to ensure system stability, resilience, and high performance. Agile Collaboration: Working within an Agile/Scrum framework, using Jira and Confluence for documentation, tracking, and sprint activities. Your Profile Experience: Junior: ~1 year of experience in backend/API development. Medior: ~3 years of solid experience in API & middleware development. Senior: 10+ years of deep expertise in complex enterprise integration and software development. Core Technical Skills: Proficient in Java development applied to APIs. Strong knowledge of API/Web Service standards and protocols ( OAuth2, JWT, SOAP ). Hands-on experience with API Gateway / ESB platforms such as Axway, Apigee, or WSO2 . Familiarity with Event-Driven Architecture and public cloud concepts. Solid understanding of security tools and practices ( Snyk, PKI ). Experience with Git , CI/CD workflows, and web services testing frameworks. Methodology: Comfortable working in Agile/Scrum squads with tools like Jira and Confluence . Languages: Working proficiency (minimum 3/4) in English OR French/Dutch . The Recruitment Steps 🚀 First Contact: A phone call to discuss your aspirations and what we can offer you. Meeting: An opportunity to get to know each other and explore your professional background. Business Interview: A discussion with one of our experts to assess your skills and define your goals. Brand Smile Role Développement - Region Locations Brussels Remote status Hybrid Contract type Freelance