We are looking for a specialized Senior UI Developer to take full ownership of our core Component Library. As the guardian of our design system, you will maintain and evolve a high-performance library built on Vanilla JS and SCSS, deployed via NPM. You will bridge the gap between design, technical execution, and strict functional requirements, working closely with analysts to translate business needs into technical reality.

Beyond development, this role is critical to our operational resilience. You will act as a primary escalation point for UI, providing L2/L3 support and on-demand availability to ensure 24/7 production stability. Working autonomously, you will deliver pixel-perfect cross-browser experiences while empowering a team of 5-6 developers to build seamless web platforms.

 

Responsibilities:

  1. Component Library Ownership: Architect and maintain the company’s core component library using high-quality Vanilla JS and SCSS, ensuring code is lean, modular, and reusable without heavy framework dependencies.

  1. Design Translation & Fidelity: Work directly with Figma, interpreting design specs, variables, and prototypes to accurately translate them into pixel-perfect, reusable code components that match the designer's vision.

  1. Accessibility (A11y) Leadership: Act as the subject matter expert for accessibility; build components that strictly adhere to WCAG guidelines and ARIA standards, ensuring inclusive experiences for all users.

  1. Release & Package Management: Manage the deployment lifecycle of the library as an NPM package. Maintain parallel versioning streams (production vs. development) to ensure stability while facilitating rapid iteration.

  1. Cross-Platform & Device Assurance: Execute rigorous multi-device testing using platforms like BrowserStack to guarantee performance. You must ensure seamless functionality across all major browsers (Chrome, Firefox, Edge, and specifically Safari on iOS) and various screen sizes.

  1. Integration Support: Collaborate closely with the wider development team (5-6 developers), helping them integrate your Vanilla JS components into their TypeScript, React, or Next.js projects.

  1. Operational Resilience & Support: Thrive in a high-pressure environment, managing competing priorities effectively. You must be available for critical production support and troubleshooting when necessary to ensure system uptime.

  1. Documentation & Templating: Utilize Nunjucks to create and maintain comprehensive documentation and templates, ensuring the library is easy for other developers to understand and implement.

  1. Code Quality & Standards: Working autonomously, you will set the bar for code quality. Implement linting, testing, and architectural standards to ensure the library remains maintainable and bug-free.

Requirements

  • Minimum 7 years of professional experience in web/front-end development.

  • A minimum of 5 years of hands-on experience in building and maintaining component libraries or design systems using Vanilla JavaScript (ES6+) and SCSS.

  • Demonstrable experience with server-side API integration.

  • Demonstrable experience integrating a headless CMS (Sitecore preferred, equivalent accepted).

  • C1 level (or equivalent) proficiency in spoken and written English.

  • Experience managing NPM packages, including publishing, versioning strategies (SemVer), and maintaining multiple environments (Dev/Prod).

  • Hands-on experience with cloud-based cross-browser testing tools such as BrowserStack or similar platforms to debug issues across different OS/browser combinations.

  • Expert-level knowledge of Accessibility (WCAG 2.1+, ARIA roles).

  • Proficiency in Figma; ability to inspect design files, extract assets, understand auto-layout/spacing, and translate visual designs into high-fidelity technical components.

Our offer

Within our open corporate culture, you contribute to the digital transformation of SNCB. You will have a job with social impact and ample opportunity to make your own contribution. In addition to a good work-life balance and a competitive salary, you will receive the following benefits:

  • the possibility to work remotely + flexible working hours;

  • 35 days of leave;

  • a company car + a public transport season ticket;

  • a target bonus;

  • a comprehensive insurance package (affiliation without own contribution, excl. outpatient costs for family members);

    • hospitalisation and dental care for the whole family;

    • outpatient costs (= medical costs separate from hospitalisation);

    • group insurance: supplementary pension, work disability and death (cafeteria plan);

    • accidents at work (extralegal);

  • meal vouchers and eco-vouchers;

  • net allowances for remote working and carwash + internet budget.

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Apply for this job
Location icon

Near Brussels Midi Station

Department icon

Solution Delivery​

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fulltime_permanent

Any questions?
Contact our Ypto Recruitment contact person.

Ypto Recruitment Contact
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3 reasons to choose Ypto 

Icoon uitdagingen: bergtop

Challenging projects

At Ypto, you never stand still. Every day is different and offers the opportunity to be challenged to innovate in order to find the best solution for our customer.

Maatschappelijke impact icoon

Social impact

Through your work, you contribute to the future of Belgian railways and have a tangible impact on millions of people.

Doorgroeimogelijkheden icoon

Growth opportunities

Initiative, trust and self-management are key. You will have the support of your colleagues to develop and the opportunity to grow.

Application procedure

Did you apply for a position at Ypto? Or are you curious about how our application procedure works? We follow the four steps below each time. Depending on the position, an additional interview or assessment may be required.

1

CV screening

We take a close look at your CV and check whether it matches the profile you are looking for. We may call you briefly to ask about your motivation and experience.

2

Interviews

After a successful screening, you’ll be invited to a first video interview with one of our Recruitment Partners. This conversation focuses on your motivation, experience, and expectations. A second interview will then take place on-site with the business team, where we’ll discuss the role and how your skills align with the team’s needs.

3

Reference analysis

Finally, we contact the references you will have provided. This way, we can make you out better.

4

We have a match: welcome to Ypto

Have you been selected? If so, we will be happy to draw up an attractive proposal and welcome you to our organisation.

Spontaneous application

Would you like to work with us on the future of SNCB but cannot immediately find the right vacancy? Then feel free to submit a spontaneous application. Who knows, you might soon be part of our team!