Mid/Senior React Developer (MUI 9 migration)

Job Overview We are seeking a skilled Mid/Senior React Developer to join our team.  Project Context Our client's platform is migrating all applications to MUI 9. As part of this effort, a central SSR-compatible component library will be built from the ground up. The project runs across three phases: Analysis → Piloting → Scaling. Responsibilities • Technical inventory, including CSR vs. SSR and existing implementations per application. • Build the central MUI 9-based component library. • Develop composite components: App Shell, Header, Panel Layouts, Form Structures. • Define design tokens and theme infrastructure, including colors, typography, and branding. • Implement all components to be SSR-compatible from day one, including Next.js / Service Requests. • Set up and maintain Storybook documentation, lifecycle-oriented. • Handle Figma handoff and propagate design decisions into the product. • Pilot components in real modules of selected applications. Requirements React & MUI 9 • Expert-level React knowledge, including Hooks, Context, performance, and composition patterns. • MUI v9, including migration from v4/v5, theme customization, and sx system. • Composite component design, including App Shell, Panel Layouts, and Form Structures. • Design token integration and tree-shaking, including icons and bundle optimization. SSR / CSR / Next.js • Deep understanding of SSR and CSR, including differences, implications, and tradeoffs. • Next.js, including SSR-compatible component development without retrofitting. • Ability to identify and prevent hydration issues. Library & Tooling • Building and maintaining shared component libraries, including monorepo setup. • Storybook, including documentation, controls, and lifecycle management. • TypeScript, including type-safe component interfaces. • Figma handoff and design token propagation. Architecture • Micro-frontend architectures are nice to have, especially relevant in later phases. • White-label theming and multi-tenant systems are nice to have. • CI/CD for component libraries, including versioning and publish workflows, is nice to have. Seniority • At least 5 years of relevant frontend experience. • Proven experience building or maintaining component libraries. • Experience in cross-team projects with multiple product teams. Benefits • Opportunity to participate in a cutting-edge project with a dynamic and innovative team. • Professional growth through engagement in technical interviews and project development phases. • Remote work (Poland). • Unique TEAL culture, relationship- and respect-driven community, non-corporate atmosphere. • Agile approach and no bureaucracy. • Outstanding integration trips to various places in Europe for all employees. • Activities to support your well-being and health. • Luxmed Gold Extended medical care and Multisport Plus benefit. • Engagement in innovative projects within a supportive and collaborative environment. • Flexible working arrangements to promote work-life balance. • Access to modern tools and technologies to enhance productivity.