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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Fullstack Engineer - **Company:** Kayzen - **Location:** Berlin, Germany (Remote available) - **Experience:** Expert - **Contract:** Permanent contract - **Skills:** JavaScript (Programming Language), Application Programming Interfaces (APIs), Artificial Intelligence, HTML5, Browser Compatibility, Cascading Style Sheets (CSS), Code Review, Cursor (Graphical User Interface Elements), Open Source Technology, Performance Tuning, Recommender Systems, Ui Patterns, Responsive Web Design, Software Engineering, TypeScript, Chatbots, ReactJS, Large Language Models, Cypress (Programming Language), Caching, Technical Debt, Backend, Vue.js, AngularJS, Playwright, Production Code, Real Time Data, Graphql, React Redux, Restful APIs - **Published:** July 3, 2026 - **Apply:** https://de.indeed.com/viewjob?jk=efb2f7a59e4a75a0 ## About the Role * 5+ years of professional Fullstack development experience with modern JavaScript/TypeScript * Solid expertise in at least one major framework (React, Angular, or Vue) and its ecosystem * Strong understanding of HTML5, CSS3, responsive design, and cross-browser compatibility * Experience building data-heavy UIs, ideally including real-time data visualization * Good grasp of Fullstack performance optimization, including bundle size, rendering, lazy loading, and caching strategies * Experience with state management patterns (Redux, MobX, Zustand, or similar) * Working knowledge of Fullstack testing methodologies, unit, integration, and end-to-end (Jest, Cypress, Playwright, or similar) * Comfortable working with design systems and shared component libraries * Experience using AI-assisted development tools (e.g., Claude Code) to boost engineering productivity, * Experience contributing to Fullstack architecture decisions on production applications * Solid understanding of APIs, RESTful services, GraphQL, and system design fundamentals * Ability to give and receive constructive feedback through code reviews * Good communication skills, able to explain technical decisions clearly to teammates and stakeholders, * Bias for shipping and iteration, you deliver incrementally and learn from real users * Comfortable with ambiguity and rapid change in a fast-paced environment * Thinking in terms of leverage and reuse, not one-off solutions * Pragmatic about trade-offs between perfectionism and speed of delivery, * Developers who prefer working in isolation on narrowly scoped tickets without engaging with the wider product context. We need someone who wants to understand the "why" behind the work and contribute ideas, not just execute tasks., * Familiarity with ad-tech, real-time bidding platforms, or high-traffic data products * Contributions to open-source Fullstack projects or community involvement * Experience building Fullstack interfaces for AI/ML-powered products (e.g., chatbots, recommendation engines, AI-generated content displays) * Familiarity with LLM APIs and prompt-driven UI patterns ## Description We are looking for a coding-first Fullstack Engineer who thrives on turning complex product requirements into high-performance UIs. You should be comfortable working across the stack, contributing to architecture discussions, and be an early adopter of AI-assisted engineering (e.g., Claude Code, Cursor, Copilot) in your daily coding workflow. This role is a strong individual contributor position with room to grow into deeper technical ownership over time. Responsibilities * Core responsibilities * + Design, build, and maintain high-quality features across the Fullstack stack, from UI to API integration + Write clean, well-tested, production-ready code and actively participate in code reviews + Collaborate closely with Product, Design, QA, and Backend teams to deliver cohesive, user-centric features + Contribute to technical decisions around architecture, tooling, and best practices within the team + Take ownership of features end to end, from planning through deployment and monitoring * Hands-on AI Implementation * + Integrate AI-powered coding agents and automated LLM-based testing into your daily development cycle + Contribute to building 'AI-First' UI patterns, working alongside the LLM Platform team on generative, prompt-driven interfaces + Stay current with emerging AI-assisted development tools and bring relevant ones back to the team * Project & Execution Management * + Break down assigned product requirements into clear, actionable engineering tasks + Deliver work reliably within sprint commitments, flagging blockers or scope changes early + Balance new feature delivery with addressing technical debt in the codebase you work on ## Related Videos - [Lessons learned from building a thriving Vue.js SaaS application](https://www.wearedevelopers.com/videos/1666-lessons-learned-from-building-a-thriving-vue-js-saas-application) - [The Resilience of the World Wide Web](https://www.wearedevelopers.com/videos/1281-the-resilience-of-the-world-wide-web) - [Putting the Graph In GraphQL With The Neo4j GraphQL Library](https://www.wearedevelopers.com/videos/257-putting-the-graph-in-graphql-with-the-neo4j-graphql-library) - [But, you're not Facebook](https://www.wearedevelopers.com/videos/378-but-you-re-not-facebook) - [Can SVG be fast? 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