Frontend Developer

Zellerfeld; Hamburg; On-site; EUR 90,000 - 130,000; Full time

Job summary

Zellerfeld in Hamburg seeks a senior frontend engineer to join a small team building the factory of tomorrow. You will refactor and optimize existing software and create new tools spanning from footscan to production to the consumer.

You will own features end-to-end, drive architecture, champion performance and security, and mentor other frontend developers while collaborating closely with hardware and operations teams at our Hamburg office.

Qualifications

• Senior-level React and TypeScript experience in production frontend systems.
• Ability to make architectural decisions about patterns, abstractions, and where to draw the line between shared and bespoke.
• Experience with performance optimization and data-fetching strategies.
• Frontend security awareness beyond auth-token plumbing.
• Ability to work with ambiguity and make decisions when requirements aren't fully formed.
• Office in Hamburg with close collaboration with hardware team is required.

Responsibilities

• Drive frontend architecture across our three product surfaces, making decisions about patterns, boundaries, and shared infrastructure that hold up over time.
• Own features end-to-end: from the design conversation through implementation, production rollout, and debugging sessions.
• Lead on performance, scalability, and observability, including Core Web Vitals and instrumentation on hardware-adjacent side.
• Apply frontend security rigor, addressing XSS, CSRF, CSP, and dependency risks.
• Translate vague product/hardware needs into technical direction and decide between fast solutions or durable ones.
• Collaborate with hardware engineers on production UIs and with operations on scanning and in-store experiences.
• Mentor other frontend developers and help establish scalable engineering practices.

Skills

React

TypeScript

Frontend architecture

Performance optimization

Frontend security

Mentoring

Education

Formal CS background

Job description

Zellerfeld is revolutionising the footwear industry with the world’s first 3D-printing technology for fully customizable shoes. Our goal is simple: printed shoes on every foot. We’re a passionate team of engineers, designers, and innovators, questioning the status quo and disrupting traditional manufacturing processes. Backed by founders, influencers, and celebrities who believe in our vision, we’re committed to making a lasting, positive impact—not just on the footwear industry, but on the world.

Your Mission

You’ll be part of a small team of software developers building the factory of tomorrow. Your job will be to refactor and optimize existing software and the development of new tools and services from footscan via production to the consumer. As a part of our development team, you will find solutions for problems you never heard of and extend your knowledge daily.

What you'll do

• Drive frontend architecture across our three product surfaces, making decisions about patterns, boundaries, and shared infrastructure that hold up over time
• Own features end-to-end: from the design conversation through implementation, production rollout, and the inevitable debugging session when something behaves differently on the factory floor than it did in staging
• Lead on performance, scalability, and observability. Core Web Vitals on the consumer side, realtime responsiveness on the hardware-adjacent side, and the instrumentation that lets us know which is broken
• Apply frontend security rigor. Not just "we use auth tokens," but a working understanding of XSS, CSRF, CSP, dependency risk, and the everyday vulnerabilities that ship to production when nobody's watching
• Navigate ambiguity: translate vague product, hardware, or operational needs into technical direction, and know when to ship a fast solution versus invest in a durable one
• Collaborate directly with hardware engineers on the production-side UIs and with operations on scanning and in-store experiences. The feedback loop is short and the requirements are real
• Mentor other frontend developers, review code with intent, and help establish the engineering practices that scale with the team

Your profile

• Senior-level React and TypeScript experience, with a track record of owning non-trivial frontend systems in production
• Demonstrated ability to make architectural decisions about patterns, abstractions, and where to draw the line between shared and bespoke
• Performance and scalability work on real systems. Not just Lighthouse scores, but render performance, bundle discipline, data-fetching strategy, and caching
• Frontend security awareness beyond auth-token plumbing. You understand the common attack surface and how to avoid expanding it
• Comfort with ambiguity and the judgment to make decisions when requirements aren't fully formed
• As a company specializing in both hardware and software, we value close collaboration within our team. Therefore, we are seeking candidates who can join us at our office in Hamburg.

Nice to have

• Experience with realtime, hardware-adjacent, or kiosk/in-store frontends
• Manufacturing, production, or operational-tooling context
• 3D, WebGL, or product-visualization experience (Three.js, R3F)
• PWA and/or native (React Native, Capacitor) experience
• Background contributing to design systems or frontend platform work

Background

We care about what you can do, not where you learned it. Formal CS background, bootcamp, apprenticeship, serious open-source contributions, or a strong portfolio of shipped work, all valid signals.