Senior JavaScript Engineer

We are looking for a Senior JavaScript Engineer with 3–6 years of experience and a strong background in frontend development, web performance optimization, and Real User Monitoring (RUM). In this role, you will design and develop lightweight JavaScript monitoring agents that capture application performance, browser metrics, user interactions, and errors across modern web applications. You will collaborate closely with backend and APM teams to deliver industry-leading observability solutions that enhance the digital experience for end users. Key Responsibilities Design, develop, and maintain JavaScript-based Real User Monitoring (RUM) agents for modern web applications. Build lightweight browser agents that capture performance metrics, user interactions, and application errors with minimal overhead. Utilize Browser Performance APIs such as Navigation Timing, Paint Timing, Performance Observer, and Long Tasks API. Implement monitoring for Core Web Vitals, including LCP, FID, CLS, and INP. Optimize monitoring agents for performance, scalability, and cross-browser compatibility. Collaborate with backend and Application Performance Monitoring (APM) teams to correlate frontend and backend performance data. Debug, troubleshoot, and optimize JavaScript code for performance and reliability. Stay updated with emerging web technologies, W3C standards, and browser APIs. Participate in code reviews and contribute to engineering best practices. Work closely with cross-functional teams to deliver high-quality observability solutions. Key Skills & Qualifications 3–6 years of professional experience in JavaScript and TypeScript development. Strong expertise in JavaScript, TypeScript, and modern frontend development. Hands-on experience with Browser APIs and event-driven programming. Strong understanding of web performance monitoring and performance optimization techniques. Experience implementing and monitoring Core Web Vitals (LCP, FID, CLS, INP). Familiarity with Browser Performance APIs, including: Navigation Timing API Paint Timing API Performance Observer API Long Tasks API Experience with frontend frameworks such as React, Angular, or Vue.js. Knowledge of cross-browser compatibility, browser debugging tools, and developer tools. Experience with compression technologies such as Gzip and Brotli. Exposure to Real User Monitoring (RUM) or frontend monitoring tools such as: New Relic Datadog RUM Dynatrace Sentry Apply by sending your CV to careers@cliqhr.co.in