Fullstack Developer
Build and refactor features end-to-end, across interfaces, production tooling, and consumer-facing apps
Develop and integrate REST and GraphQL APIs — both sides of the contract
Create responsive, polished frontends that translate design intent into production UI
Work with Docker as part of normal development and deployment
Make architectural and product decisions, not just implement them
Collaborate closely with backend, frontend, design, and hardware teammates
Continuously raise the quality bar: performance, testing, and code health on both sides of the stack
Own product and platform flows end-to-end: design, build, ship, operate, and improve. Not "frontend with backend tickets," and not "backend with React on the side." Real ownership across both sides of the API
Drive architectural decisions that span the stack: where logic lives, how data flows, how systems stay coherent as they grow
Operate production systems. Debug across browser, API, queue, database, and infrastructure, and improve observability so the next person doesn't have to start from scratch
Lead on performance and scalability on both sides: frontend render performance, bundle and asset strategy, backend query and queue performance, caching, async processing
Apply real security awareness across the stack: authentication and authorization done correctly, common exploits avoided by design (injection, SSRF, broken access control, XSS, CSRF), and dependency hygiene
Navigate the everyday tradeoff between shipping fast and building sustainable systems, and explain your reasoning to people who aren't engineers
Collaborate directly with hardware engineers on production-side workflows, and with operations on scanning and consumer-facing flows
Mentor other engineers and help establish the practices (reviews, testing, deployment, on-call) that scale with the team
Senior-level experience as a full-stack engineer who has genuinely owned both sides. Not a frontend dev with backend tickets, not a backend dev who occasionally touches React
Strong React, TypeScript, and Next.js on the frontend; strong Node.js fundamentals
Demonstrated architectural judgment across the stack: knowing where to put logic, when to introduce abstractions, when to extract a service
Production operations experience: debugging real incidents end-to-end across browser, API, queue, database, and infrastructure
Performance and scalability work on both sides, on systems with real load
Security awareness beyond basic auth. You understand the common attack surface and design to avoid it
Comfort with ambiguity and the ability to drive technical direction independently
Big advantage
Laravel, Laravel Nova, and PHP — this is our primary backend stack, and full-stack here genuinely means full-stack
Tailwind CSS
Docker as part of normal development and deployment
Solid relational database work (MySQL); exposure to non-relational stores (MongoDB, InfluxDB) is a plus
Background
We care about what you can do, not where you learned it. Formal CS background, apprenticeship, serious open-source contributions, or a strong portfolio of shipped work, all valid signals.
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.