Senior Frontend Developer, AI Applications

FashionUnited; Aarhus; On-site; DKK 750,000 - 1,050,000; Full time

Job summary

BESTSELLER is seeking a Senior Frontend Developer to drive frontend design in AI applications within the Appretio platform. You will translate data-heavy requirements into high-performance interfaces, mentor engineers and shape production frontends at scale.

You will collaborate with merchandisers, data scientists and engineers to set technical direction, apply UI/UX best practices and ensure reliable, responsive user experiences in a data-driven landscape.

Qualifications

• Experience building production-grade frontends for data-heavy analytics.
• Strong leadership and mentoring capabilities.
• Proficient in React/TypeScript with modern frontend tooling.
• Fluent English communication across technical and non-technical teams.

Responsibilities

• Design and deliver frontend features for a data-heavy analytics app.
• Drive frontend architecture decisions for performance and maintainability.
• Apply UI/UX best practices to complex analytics workflows.
• Collaborate with product, data science and backend teams to translate needs into seamless UX.
• Monitor, debug and optimise frontend apps for reliability and speed.
• Mentor engineers and raise engineering standards across the team.

Skills

Mentoring engineers

Strong communication

Fluent English

Frontend craftsmanship

UI/UX awareness

Education

Bachelor's degree in Computer Science or related field

Tools

React

TypeScript

Tanstack Query

Vitest

Playwright

Storybook

Vanilla Extract

Ag Grid

Ag Charts

Job description

Senior Frontend Developer, AI Applications

Join our pioneering team at BESTSELLER as we embrace the power of data science and AI to redefine the retail and e-commerce landscape. We are looking for a seasoned Senior Frontend Developer who is deeply passionate about turning complex data into intuitive, high-performance interfaces, and ready to take a leading technical role in shaping the next generation of our AI applications.

This role places you at the heart of our Appretio platform, our commitment to revolutionising merchandising through data-driven solutions.

YOUR TEAM
You will be an integral part of a dynamic team within the Merchandising Solutions department, a group of specialists working to improve how we make merchandising decisions at BESTSELLER. Your closest team consist of ten highly skilled professionals, all committed to harnessing the potential of data to enhance customer experience, streamline operations, and drive revenue growth working across merchandising, data science, engineering and analytics. Together, we build data-driven tools that turn complex data into something our colleagues can use to make better decisions.

YOUR ROLE
In the Appretio team, you will lead the way in how we design and build the interfaces where data-driven decisions are made at scale. You will work alongside merchandisers, data scientists, engineers and analysts, setting the technical direction for how we build, deploy and operate production frontends.
Your challenge? To raise the bar on how data becomes usable in the hands of the business, and to mentor and guide others as our AI applications continue to develop.

Your responsibilities include:

• Designing and delivering frontend features for a data-heavy analytics application with substantial data loads, setting technical standards for the team.
• Driving architectural decisions across the frontend stack, balancing performance, scalability, maintainability and time-to-value.
• Applying UI/UX best practices to complex analytical workflows, balancing aesthetics with clarity and functionality.
• Partnering closely with product owners, merchandisers and backend developers to translate complex business needs into seamless user experiences.
• Monitoring, debugging and optimising applications to maintain high standards of reliability and responsiveness.
• Mentoring and coaching fellow engineers, reviewing code and helping raise engineering standards across the team.

YOUR BENEFITS
Joining BESTSELLER means working in a vibrant, innovative environment where your decisions make immediate, tangible impacts. You will:

• Engage with an expert, collaborative team committed to innovation and excellence.
• Access comprehensive professional growth opportunities, including specialised training programmes and international exposure.
• Benefit from extensive support for ongoing education, certification, and skill development.

YOUR PROFILE
You are an experienced, proactive engineer who is motivated by turning complex data into interfaces people genuinely enjoy using. You thrive on collaborating closely with experts and product partners to shape efficient solutions that deliver real value, and you naturally take ownership of technical direction and quality. You bring a strong sense of craft in UI/UX, and the judgement that comes from having shipped and operated web applications in production.

We imagine that you bring:

• A degree in Computer Science, Software Engineering, or a related field.
• Several years of hands-on experience building and shipping production web applications.
• Proficiency in React and TypeScript - experience with Tanstack Query, Vitest and Playwright would be an additional plus.
• Experience with technologies such as Storybook, Vanilla Extract, Ag Grid and Ag Charts is valuable, but we don’t expect you to tick every box.
• Demonstrated experience mentoring engineers, leading technical initiatives, and setting engineering standards.
• A keen interest in UI/UX and optimising user experience, with a strong commitment to frontend craft.
• Excellent communication skills, with the ability to explain technical decisions clearly to both technical and non-technical colleagues.
• Fluency in English, both spoken and written.

Any experience with Python and APIs, AWS, Docker or Kubernetes, large-scale data visualisation, agentic development workflows or integrating AI features into user-facing applications would be an advantage.

WORK LOCATION: Your primary workplace will be at our office in Aarhus.

ABOUT BESTSELLER
At BESTSELLER, we are more than 20,000 people in 38 different countries working for over 20 fashion brands such as JACK & JONES, SELECTED, VERO MODA, ONLY, PIECES, VILA, OBJECT, MAMALICIOUS, NAME IT, NOISY MAY and Y.A.S. We are a family-owned company with a strong foundation and values to build on, empowering us to pursue the ideas we believe in to take BESTSELLER forward. We are committed to diversity and provide equal opportunities for everyone, irrespective of sex, race, ethnicity, religion or belief, disability, age, sexual orientation or gender identity. We strive to create an empowering environment where people can thrive and develop. For more information, visit www.bestseller.com.

Jobtitel:

Senior Frontend Developer, AI Applications