We are seeking a Web Development Trainee position based in our Poznań Office.

Ready to help build a better future for generations to come? 

In an ever-changing, fast paced world, we owe it to ourselves and our future generations to live life responsibly. At ROCKWOOL, we work relentlessly to enrich modern living through our innovative stone wool solutions.

Join us and make a difference!

About the role

We’re building the next generation of AI-powered applications at ROCKWOOL and we’re looking for a Web Development Trainee who’s excited to learn, ship code, and grow fast.

This is a trainee position, but not a “make coffee and fix typos” role. You’ll work with modern React and frontend tooling to design and build real features used by real users across our organization. You’ll be part of a small, cross-functional team that ships often, experiments a lot, and treats trainees as junior developers in training – not as observers.

If you’re curious, proactive, and already comfortable with the basics of React and JavaScript, you’ll fit right in.

What you will be doing

You will help design and build the frontend for our internal AI apps. More specifically, you will:

• Implement React components and views for new features and internal tools
• Work on modern UI/UX for AI workflows: chat interfaces, prompt builders, analytics dashboards, and configuration screens
• Integrate with backend APIs (REST/GraphQL) to display data, handle forms and state, and improve the user experience
• Help keep the UI accessible, responsive, and performant across devices
• Collaborate closely with designers, backend engineers, and product owners
• Learn how to build production-ready frontend code: reviews, testing, CI/CD, and good Git practices

You’ll have mentors and senior devs to support you, but you’ll also get your hands dirty with real tasks from day one.

Tech stack you’ll touch

You don’t need to know all of this on day one, but you should be excited to learn it:

• Core: React JavaScript/TypeScript, HTML5, CSS3
• State & data: React Query / SWR / context, calling REST/GraphQL APIs
• Styling & UI: CSS modules / styled-components / design systems
• Tooling: Vite / Webpack, npm/yarn, Git, code reviews via Pull Requests
• Quality: basic unit testing, linting and formatting
• AI context: working with UIs for LLM-based tools (chat flows, prompt & response handling, loading states, etc.)

We’re constantly evolving our stack, and you’ll be part of that journey.

What you’ll learn with us

During your traineeship, you’ll learn how to:

• Work in a real-world codebase with multiple contributors
• Collaborate in a product team (devs, designers, product owners, business stakeholders)
• Design and build user-friendly interfaces for complex AI tools
• Write clean, maintainable code that others can read and extend
• Use AI as a co-pilot for development (code generation, refactoring, documentation help)
• Contribute to our internal design system and frontend best practices

Our goal is that by the end of the traineeship, you’ll be ready for a Junior Frontend Developer role.

What you bring

This is a trainee role, but we do expect a solid foundation:

• Good understanding of JavaScript fundamentals
• Basics of React
• Strong grasp of HTML & CSS
• Comfortable using Git
• Basic understanding of how a web app works

If you’ve built some small projects (personal, school, hackathon) and can show code on GitHub/GitLab, that’s a big plus.

Nice-to-have (not required, but cool):

• Experience with TypeScript
• Familiarity with React Router or other routing solutions
• Some exposure to UI libraries (MUI, Chakra, Ant Design, etc.)
• Basic knowledge of testing in frontend projects
• Having used AI tools (e.g. Claude, Copilot, Cursor) in your workflow
• Understanding of accessibility and web performance basics

Don’t worry if you don’t tick all these boxes – they’re bonuses, not requirements!

You might be a great fit if you:

• Are pursuing studies in a relevant field such as computer science, mathematics or physics, and you have at least one year of studies remaining
• Enjoy learning by doing and are not afraid to ask questions
• Like working in a team, giving and receiving feedback
• Can communicate clearly in English (spoken and written)

What we offer

By joining our team, you become a part of the people-centric work environment of a Danish company. You will gain valuable experience in one of our teams which will be a good start in your professional life.

Moreover, we offer to our interns:

• team building events
• flexible working hours
• an office-first approach: option to work from home    

Also, you will work in a modern office full of comfort zones and activity places in Crown Square building. We have prepared an onboarding programme for you. This will give you the perfect opportunity to learn the process details and connect with the new team – a close-knit group of people who are always ready to help each other out. 

It could be a great opportunity to start your professional career with ROCKWOOL! 

Ready to apply?

If you recognize yourself in this profile and challenge, we kindly invite you to apply with CV written in English. If you’ve built personal, academic or hackathon projects that you’re proud of and are able to share the code (e.g., on GitHub or GitLab), feel free to include a link to your portfolio or repositories - we’d be happy to take a look.

Who we are

We are the world leader in stone wool solutions. Founded in 1937 in Denmark, we transform volcanic rock into safe, sustainable products that help people and communities thrive. We are a global company with more than 12,000 employees, located in 40+ countries with 51 manufacturing facilities… all focused on one common purpose – to release the natural power of stone to enrich modern living. Sustainability is central to our business strategy. ROCKWOOL was one of the first companies to commit to actively contributing to the United Nations Sustainable Development Goals (SDG’s) framework and are actively committed to 11 SDGs, including SDG 14, Life Below Water. Through our partnership with the One Ocean Foundation and in connection with our sponsorship of the Denmark SailGP team, we will help raise awareness around ocean health challenges in an effort to accelerate solutions to protect it.

Diverse and Inclusive Culture

We want all our people to feel valued, respected, included and heard. We employ 79 different nationalities worldwide and are committed to providing equal opportunities to all employees, promote diversity, and work against all forms of discrimination among ROCKWOOL employees. At ROCKWOOL, you will experience a friendly team environment. Our culture is very important to us. In fact, we refer to our culture as “The ROCKWOOL Way”. This is the foundation in which we operate and is based upon our values of ambition, responsibility, integrity and efficiency.