Junior Frontend Engineer Traineeship

Job description

At Castor, we pride ourselves on providing a user friendly electronic data capture platform for medical professionals. As we scale,  so do our ambitions, and we want you to help us take the next step in the evolution of our UI and UX.


Your profile:

We are looking for a Junior Frontend Engineer with a strong interest in UI and user experience,  for a 6-month traineeship with the opportunity to extend. At Castor, you will work closely with our product designers, product owners, QA and front-end engineers to help build the underlying UI components for the next generation of our products.


  • You are looking to start your career as a front-end engineer and you aspire to specialize in building good user experiences for every user.

  • You want to work in an environment where designers and engineers work hand-to-hand to deliver the best outcomes for our users. 

  • You have already worked on a Javascript-based application or web platform, or you contributed to an open source project.

  • You are comfortable working in an ES6 / Javascript environment.

  • You are an EU resident legally allowed to work in the Netherlands.


Your project:

As part of the Design team, you’ll contribute to the growth and definition of our design system by developing components and tools for Castor’s shared UI library. Ultimately, we are aiming to create a component library that will free our engineering team from any UI-related work. 


  • Build React UI components in close collaboration with our design team

  • Contribute to the improvement of our pipelines and workflows (Node scripts, integration between design tooling and our UI library)

  • Support our teams in making the right decisions when it comes to using our component library and improving accessibility

  • Ensure the maintainability of this project by contributing to its documentation and the test coverage of our packages (unit and functional tests)

  • Continuously analyze and follow UI and design systems trends to apply emerging best practices in our workflow

Our toolbox:

One of the core values of the Design System team is to ensure the quality and accessibility of our platforms through our shared component library and a series of shared tools.


This system is centered around:

  • a React-based component library, using TypeScript and styled-components

  • a series of Node scripts to ensure a seamless continuous delivery pipeline

  • a strong testing framework using Jest and a series of React testing libraries

  • a focus on documentation using Storybook and a series of open-source inspired documents to empower all our engineers to use and contribute to our tools.

  • and a series of shared configuration for systems like BabelJS, Webpack, ESLint, Prettier, etc.


Your development:

You’ll be surrounded by a team of passionate, caring, opinionated and open-minded people who’ll help you grow your technical and collaborative skillset.


As our Junior Frontend engineer, you will develop:

  • Your Javascript (TypeScript, React and Node), HTML and CSS skills on a rapidly evolving project helped by colleagues with many years of professional experience.

  • Your collaboration skills and learn how to balance business- and user-needs by being between Product and Engineering teams

  • How to express yourself in a direct but supportive company culture.

  • How to create scalable design systems and component libraries by joining this project at an early stage. 

  • How to design and develop accessible and inclusive interfaces following international guidelines used by the industry.


Our offer:

  • Six months traineeship with the opportunity to extend to a one year contract

  • Compensation package including 30 holidays annually, pension & company bonus

  • Working in a supportive, rapidly growing team that’s helping clinical researchers worldwide

  • Fresh and healthy lunch and snacks, and company outings

  • Flexible working with the option to work from home one day per week

  • Shiny new office in the Amstel area

  • Fun and experienced international team to work with


Your future teammates:


   Chris Pattison     Chris Pattison  |  Product Design Manager


   Damien Senger     Damien Senger  |  Design systems & Accessibility Lead


   Ross Tuck     Ross Tuck  |  Principal Engineer