Senior React Developer (Architecture & Ownership) | AI Product

Polcode is a global software house with over 100 professionals working on digital businesses, software platforms, eCommerce stores, websites, and apps. The role is for a long-term project with an international client based in Berlin, building an advanced AI-powered evaluation platform focused on testing AI agents in simulated scenarios and monitoring their real-world performance.

• Strong commercial experience as a Senior React Developer
• Deep, hands-on knowledge of React and TypeScript (including advanced TypeScript concepts)
• Strong understanding of frontend and web application architecture
• Ability to design scalable solutions and make independent architectural decisions
• Experience working with APIs (REST, WebSocket-based communication)
• Experience with styled-components (v6) and modern frontend tooling
• Strong ownership mindset and ability to work independently
• Willingness to take on a principal-level role when needed (technical leadership, mentoring, decision-making)
• Excellent communication skills and ability to collaborate in an international team
• Fluent English (daily direct communication with client and engineering team)

Nice to have:

• Experience with microfrontends architecture
• Experience with Next.js
• Understanding of server-driven UI concepts
• Familiarity with Atomic Design methodology
• Experience building or maintaining design systems / shared UI libraries
• Experience working with monorepos (Nx, Turborepo, pnpm, yarn workspaces)

• Design and build a reusable frontend scaffold/platform for future applications
• Contribute to rewriting a monolithic frontend into a microfrontends architecture
• Implement real business applications on top of the platform
• Make pragmatic architectural decisions and influence technical direction
• Work closely with backend engineers building scalable, low-latency microservices (Python)
• Collaborate directly with technical stakeholders and development teams
• Mentor other engineers and support knowledge sharing when needed
• Write clean, maintainable, production-ready code and contribute to engineering standards

100% remote work within Poland only