Senior Full-Stack Engineer: Scalable Web Apps & APIs

SEIDOR; Brussel Hoofdstad; On-site; EUR 90,000 - 130,000; Full time

Job summary

SEIDOR in Brussels is seeking a senior Full Stack Software Engineer to design, develop, and maintain scalable web applications across front-end and back-end layers, with API integration and cloud deployment via CI/CD.

You will work in cross-functional teams, ensure code quality, security, and performance, and contribute to documentation and testing. A track record in complex software environments is highly valued.

Qualifications

• Computer Science, Engineering or equivalent Degree related
• 15 years of IT related experience
• 3 years of experience in international/intergovernmental organizations or central national administrations
• 1 year of experience in pharma, health or agrifood sectors
• Experience using Java and Java Enterprise (JDK 11+; JEE 7+) with middleware such as Oracle WebLogic (14+), TomEE or IBM WebSphere
• Experience developing and maintaining features across the full stack—from UI to API to database
• 3 years of experience with version control systems (Git, SVN) and CI toolchains (Bamboo, Jenkins)
• 5 years of experience in core frontend languages (JavaScript, HTML, CSS)
• 5 years of experience in modern frontend frameworks (Angular, React, Vue, Bootstrap, Dojo)
• 5 years of experience with relational databases (Oracle, PostgreSQL)
• 5 years of experience designing, building, securing RESTful APIs and web services
• 5 years of experience checking detail in code, error handling, and documentation
• 5 years of experience in root-cause analysis and debugging across software stack
• One certification in Java SE/Java EE/Oracle/IBM/Cloud computing

Responsibilities

• Design, develop, and maintain scalable full-stack web applications (front-end, back-end, database)
• Develop responsive user interfaces and server-side business logic
• Design, develop, and integrate APIs for seamless component communication
• Write clean, reusable, secure, well-documented code
• Implement authentication, authorization, input validation, secure storage, and monitoring
• Optimize performance, functionality, and cross-browser/device compatibility
• Perform unit and integration testing, debugging, and code validation
• Deploy and manage applications on cloud platforms using CI/CD pipelines and containers
• Collaborate with front-end and back-end teams for system integration
• Ensure solutions meet functional and non-functional requirements, maintain documentation and code quality

Skills

Analytical thinking

Root-cause analysis

Documentation

Team collaboration

Security best practices

Testing

Problem solving

Education

Bachelor's degree in Computer Science, Engineering or related

Tools

Java

Java Enterprise (JEE)

Oracle WebLogic

TomEE

IBM WebSphere

JavaScript

HTML

CSS

Angular/React/Vue/Bootstrap/Dojo

RESTful APIs

Git

Jenkins/Bamboo

Job description

SEIDOR in Brussels is seeking a senior Full Stack Software Engineer to design, develop, and maintain scalable web applications across front-end and back-end layers, with API integration and cloud deployment via CI/CD.

You will work in cross-functional teams, ensure code quality, security, and performance, and contribute to documentation and testing. A track record in complex software environments is highly valued.