Develop a lightweight, efficient JavaScript script to track user interactions (clicks, scrolls, form submissions, etc.).
Monitor AJAX requests and log network activity to capture API calls and responses.
Detect DOM changes in real-time using MutationObservers and other native browser APIs.
Implement efficient event listeners and minimize performance overhead.
Hook into browser native functionalities (e.g., intercepting network requests, modifying prototypes, overriding built-in methods) to extract relevant data.
Optimize script execution, memory usage, and CPU performance to ensure smooth operation without affecting the site.
Work with CORS limitations, handling API authentication when required.
Ensure cross-browser compatibility and robust error handling.
Optimize data collection and transmission while ensuring compliance with privacy and security policies.
Collaborate with backend teams to send collected data via APIs securely.
Requirements: 5+ years of experience in Vanilla JavaScript (ES6+).
Strong knowledge of DOM manipulation, Event Handling, and Asynchronous JS (Promises, Fetch, WebSockets).
Experience with MutationObserver, PerformanceObserver, and IntersectionObserver.
Proficiency in monitoring AJAX calls, intercepting XHR/Fetch API, and modifying built-in browser functions when necessary.
Deep expertise in performance profiling, script optimization, and debugging tools (Chrome DevTools, Lighthouse, WebPageTest, etc.).
Deep understanding of CSS and HTML, including stylesheets, rendering behavior, and dynamic styling techniques.
Familiarity with browser storage (LocalStorage, SessionStorage, IndexedDB) for temporary data caching.
Understanding of security concerns (CORS, CSP, Same-Origin Policy, etc.).
Experience in data collection while ensuring GDPR and privacy compliance.
Ability to write clean, optimized, and well-documented JavaScript code.
This position is open to all candidates.