Senior Frontend UX Engineer

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Frontend UX Engineer based in Brazil. Join a fast-moving engineering team building an innovative AI-powered workspace that transforms how people interact with information and collaborate with intelligent systems. As a Senior Frontend UX Engineer, you will create intuitive, responsive, and visually polished experiences that make complex workflows feel effortless. You will help shape a visual canvas where users combine interactive components to generate real-time insights and enable intelligent automation. Working closely with product management, design, and backend engineering, you will influence both product direction and implementation quality. This role combines advanced frontend engineering, UX thinking, and creative problem-solving in an environment that values autonomy and experimentation. Your work will directly influence how professionals experience the next generation of AI-first tools.

As a Senior Frontend UX Engineer, you will lead the development of user-facing features while ensuring that every interaction is intuitive, accessible, performant, and visually refined. Your responsibilities will include: Lead the end-to-end implementation of frontend features, from initial concepts and technical decisions through development, testing, and release. Translate design concepts into seamless, responsive, accessible, and high-performance user experiences. Build and refine interactive interfaces for a visual AI workspace, including dynamic components, real-time dataflows, and collaborative experiences. Collaborate with product management, the design council, and backend engineers to create interactions that balance usability, functionality, and technical feasibility. Simplify complex workflows and anticipate user needs to make powerful product capabilities easy to understand and use. Pay close attention to visual details, micro-interactions, animations, transitions, typography, color, and spacing to deliver polished interfaces. Optimize frontend performance through techniques such as lazy loading, memoization, and bundle optimization. Apply accessibility standards and responsive design principles to ensure a consistent experience across devices and user needs. Challenge existing specifications when necessary and propose improvements that strengthen the overall product experience. Contribute to frontend development standards, reusable components, and design systems as the engineering team grows. Promote engineering quality and reduce rework through thoughtful implementation, collaboration, and attention to detail. Requirements: The ideal candidate combines advanced frontend development expertise with a strong design sensibility, product mindset, and passion for creating exceptional user experiences. You should be comfortable working in an evolving environment where initiative, collaboration, and craftsmanship are essential. Key qualifications include: Expert-level proficiency in React and ideally experience with Next.js or comparable server-side rendering frameworks. Strong experience building real-time applications, including familiarity with WebSockets and collaborative state-management patterns such as CRDTs or operational transformation (OT). Deep knowledge of CSS architecture, animation libraries, and techniques for creating precise, polished user interfaces. Experience optimizing frontend performance, including lazy loading, memoization, and JavaScript bundle optimization. Strong understanding of web accessibility standards, including WCAG, and responsive design principles. A user-centered approach to product development, with the ability to balance ease of use, flexibility, and advanced functionality. Proven ability to turn complex workflows into clear, elegant, and intuitive interactions. Excellent visual judgment, particularly in motion, micro-interactions, typography, color, spacing, and interface consistency. Experience developing collaborative or highly interactive applications, such as tools similar to Figma, Notion, Miro, or Google Docs. A proactive, product-first mindset, with the confidence to challenge specifications and recommend better solutions. Comfort working with ambiguity, exploring ideas, and contributing to feature development beyond predefined tickets. Strong communication and collaboration skills when working with designers, product managers, and backend engineers. A self-directed, curious, and hands-on approach, with a commitment to shipping high-quality, impactful features. Interest in helping establish and scale frontend best practices and design systems as a team and product evolve. Benefits: Competitive compensation: A competitive salary aligned with the role and experience. Equity participation: The opportunity to participate in the company's growth through stock plans. Remote-first flexibility: Work in a remote-first environment with flexibility in how you organize your work. Meaningful ownership: Join at an early stage of the engineering team's growth and help shape product direction and technical practices. Creative engineering environment: Work on emerging technologies, including AI, autonomous agents, innovative user interfaces, and reactive dataflows. Professional impact: Contribute ideas and deliver features that can influence how professionals collaborate and work with AI. Collaborative culture: Work alongside ambitious, passionate colleagues who value craftsmanship, autonomy, experimentation, and user-focused design. Opportunity to shape the future: Help build both the product and the engineering culture as the team scales.