The Senior Full-Stack Connectivity Engineer will analyze third-party client-side web solutions, design and maintain Node.js middleware, and develop React 18 single-page apps. They will work in an agile environment, manage service dependencies, participate in code reviews, and ensure full-cycle feature delivery. The role requires a deep understanding of JavaScript, browser internals, and networking fundamentals. The engineer will need to write clean, testable code and have good UX sensibility. The job involves reverse engineering, inspecting network traces, and utilizing various tools. The engineer will need to have confident Git workflow and team development habits. Must be a fluent Russian speaker and have a B1+ level of English proficiency.