Fullstack Developer - Shopify

You'll be our go-to Shopify expert, pushing the boundaries of what the platform can do to build the world's most advanced on-demand manufacturing experience. From custom app development and theme architecture to deep API integrations with our production systems, your work will transform our Shopify store into the central operating system behind Zellerfeld's vision of sustainable, custom-fit footwear. You'll own the platform end-to-end — shaping both its technical foundation today and its headless future tomorrow.

• Build and maintain custom Shopify Apps that power our on-demand manufacturing, foot-scanning, and recycling programs

• Architect and develop our Shopify theme using Liquid, JSON templates, and modern JavaScript

• Design integrations between Shopify Plus and our manufacturing systems, ERP, and logistics partners

• Define the platform's data architecture — Metafields, Metaobjects, and the structures that hold a non-standard product model together

• Research and prototype a headless architecture as the next step in the platform's evolution

• Use Shopify Functions and Flow to customize checkout logic and automate operational workflows

• Monitor and optimize Core Web Vitals, speed, and conversion across the storefront

• Mentor other developers and establish Shopify best practices as the team grows

Required:

• Proven ability to build, deploy, and maintain custom Shopify Apps from scratch — including Shopify CLI, OAuth, and webhooks

• Deep theme development expertise: Liquid, Sections, Blocks, JSON templates, and modern JS for interactive experiences

• Expert-level work with Shopify's APIs — both Storefront (GraphQL) and Admin (REST and GraphQL)

• Strong React, JavaScript/TypeScript, and modern HTML/CSS fundamentals

• Architectural judgment: knowing when to reach for a theme change, a custom app, a Function, or a headless build

• Headless frameworks (Next.js, Remix, or Shopify's Hydrogen/Oxygen)

Nice to have:

• Hands-on experience with Metafields and Metaobjects for complex product/content modeling

• Shopify Functions and Flow in production

• CI/CD setup and management

• Performance tooling (Lighthouse, WebPageTest, browser profiling)

• Experience integrating Shopify with manufacturing systems, ERP, or fulfillment platforms

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.