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# Senior Frontend Developer

- **Company:** Seidor
- **Location:** Brussel, Belgium
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Clean Code Principles, Java (Programming Language), JavaScript (Programming Language), Adaptive Design, Application Performance Management, HTML5, User Authentication, Unit Testing, Oracle WebLogic Server, Bootstrap (Software), Cascading Style Sheets (CSS), Command-Line Interface, Software Quality, Continuous Integration, Data Validation, Data Security, Relational Databases, Software Debugging, Dojo Toolkit, ECMAScript, Middleware, Java Platform Enterprise Edition (J2EE), Monitoring of Systems, Java Development Kit, PostgreSQL, OAuth, Oracle (Applications), Web Application Security, Data Streaming, Subversion, TypeScript, Web Applications, Web Application Frameworks, Website Wireframe, ReactJS, Git, Vue.js, Webpack, AngularJS, Front End Software Development, Device Compatibility, Splunk, Software Version Control, Dynatrace, Atlassian Bamboo, Jenkins, Programming Languages
- **Published:** October 26, 2026
- **Apply:** https://www.indeed.com/viewjob?jk=f6c430bbd1673c79

## About the Role

* Computer Science, Engineering or equivalent Degree related
 * Minimum 12 years of IT related experience
 * 5 years of experience working in international/intergovernmental organizations or central national administrations
 * 12 years of experience in HTML5, JavaScript, ES6 and CSS3.
 * 12 years of experience of building complex, modular client-side applications using modern frameworks, Web Components, and state management patterns.
 * 12 years of experience developing responsive and adaptive design.
 * 12 years of experience using version control systems (such as Git, SVN or equivalent) and continuous integration toolchains (such Bamboo, Jenkins or equivalent).
 * 5 years of experience developing with fundamental front-end languages such as HTML5, JavaScript, ES6 and CSS3 or equivalent.
 * 5 years of experience using front-end web frameworks (such as AngularJS, Angular, React, Vue, Bootstrap, Dojo or equivalent)., * 3 years of experience in Angular (v14+), Bootstrap, and TypeScript, including build tooling (such as Angular CLI, Webpack, Vite or equivalent).
 * 3 years of experience in Web security, authentication and authorization protocols (such as OAuth, Open ID Connect or equivalent).
 * 3 years of experience in front-end testing frameworks and tools (such as Jest, Karma, Cypress or equivalent) for unit and integration testing.
 * 3 years of experience in recent versions of Java and Java Enterprise (such as JDK up to at least version 11 or more recent versions, JEE up to at least version 7 or more recent versions or equivalent) or equivalent.
 * 3 years of experience in professional experience in working with relational databases (such as Oracle, PostgreSQL or equivalent).
 * 3 years of experience in middleware such as Oracle WebLogic (up to at least version 14 or more recent versions), TomEE or equivalent.
 * 3 years of experience using case management systems or similar, i.e. systems managing documents and / or files with workflow, business rules, database management and back-office functionality for querying, analysis or reporting.
 * 3 years of experience in the use of client-side monitoring tools such as Dynatrace and Splunk or equivalent.
 * 3 years of experience in web security, authentication and authorization protocols (such as OAuth, Open ID Connect or equivalent).

## Description

* Develop and maintain responsive, scalable front-end web applications using modern frameworks and technologies.

 * Design intuitive user interfaces and implement features that enhance user experience.

 * Collaborate with UX/UI designers to transform wireframes and mock-ups into functional web components.

 * Write clean, reusable, maintainable code following development best practices.

 * Implement state management solutions and ensure efficient data flow.

 * Apply security best practices, including authentication, authorization, input validation, and secure data handling.