Critical Mass - Senior Developer

London1w ago

Requirements

• 5+ years of professional front-end development experience with expert-level React and JavaScript/TypeScript proficiency • Strong understanding of modern CSS (CSS Modules, styled-components) and solid grasp of web fundamentals (semantic HTML, responsive design, performance optimization) • Experience with modern build tools and bundlers (Vite, Webpack, etc.), proficiency with Git and CI/CD workflows (GitHub Actions/Workflows) • Testing experience (unit tests, integration tests, e2e tests with tools like Jest, React Testing Library, Cypress/Playwright) • Accessibility best practices (WCAG, ARIA) and SEO fundamentals • Experience integrating frontend with external APIs and backend services • Familiarity with data formats (JSON, REST, GraphQL), knowledge of authentication and secure data handling • Experience with Supabase or similar backend-as-a-service platforms • State management experience (XState, Zustand, or similar libraries) • Component library or design system work • AWS or similar cloud platform familiarity • Experience mentoring junior developers • You may have: • Experience in Python • Proficiency with LLMs, Pydantic, LangChain/LangGraph or similar orchestration tools • Familiarity with AEM

Responsibilities

• Develop web applications that follow the latest web standards and conform to leading-edge front-end technologies • Work closely with the Creative, Business, Technology, and QA teams to ensure the solution meets the requirements and performance targets (mobile and desktop). • Own the development of web applications and ensure they follow the overall technical architecture and design established by the technical lead • Implement user and business requirements, which are composed of multiple development activities • Maintain up-to-date and complete documentation on projects as dictated by the capability’s guidelines and best practices • Debug or troubleshoot complex issues in existing web applications • Proactively provide feedback on policies and procedures when an opportunity for improvement exists • Proactively provide guidance and support to other members in fulfilling their tasks and improving their performance and overall technical skills.