Backend Developer

Your mission

You'll be part of a small team of software developers building the factory of tomorrow. As our Backend Developer, you'll design and maintain the systems that power everything — from foot scanning and production to the consumer experience. You'll write clean, scalable code, contribute to architecture decisions, and help raise the bar for quality and security across our backend infrastructure.

What you'll do

• Design and maintain the REST and GraphQL APIs that power scanning, production, and the customer-facing product

• Own services end-to-end: schema design, performance, observability, and the on-call reality that comes with live systems

• Shape architecture decisions as we evolve between monolith and selectively extracted services

• Build async pipelines and queue-based workflows that move data between hardware, production, and customers

• Write code that's tested at the unit, integration, and end-to-end level — and review code with the same standard

• Mentor teammates and raise the bar on security, performance, and GDPR-conscious design

• Collaborate closely with frontend, DevOps, hardware, and product

Your profile

• Strong PHP and Laravel experience, including Laravel Nova for internal tooling

• Deep MySQL skills — schema design, query optimization, and performance tuning under real load

• Solid grasp of REST and GraphQL API design, plus authentication patterns (JWT, OAuth)

• Comfortable with Docker, Git/GitLab, and CI/CD as part of your normal workflow

• Practical experience with caching, queues, and async processing

• Judgment about when to reach for a microservice and when not to

• A security mindset and the discipline to apply it consistently

Nice to have

• Python or Go (we use both in adjacent systems)

• AWS experience

• Background in data flow modeling or systems where backend meets hardware/IoT

Why Laravel, in case you're wondering

It's a fair question for a company doing what we do. Laravel lets a small team move quickly across a wide surface area admin tooling, customer APIs, internal services without fragmenting the stack. Where we need different tools (Python for ML-adjacent work, Go for performance-critical paths), we use them. The backend is pragmatic, not dogmatic.

Why us?

Why us?

At Zellerfeld, you will find a multidisciplinary team of engineers, SW and HW specialists, entrepreneurs, designers, and students with a common passion. We embrace contrarian thinking, humility, pushing limits, and improving ourselves. We utilize a flat hierarchy, and we want your voice to be heard. We also care about bonding because we want to be a tight-knit community, so be prepared to spend quality time with everyone, including the CEO!

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.