GitHub has developed a specialized approach to browser monitoring, emphasizing security, privacy, and performance by using internal tools rather than third-party solutions. Due to restrictive Content Security Policies, GitHub cannot use many common third-party real-user monitoring tools, so they leverage an internal system built on open-source technologies like Graphite, Nagios, and D3 to collect and analyze browser performance metrics. These metrics include detailed browser page load timings using the Navigation Timing API and simulated load times for older browsers, enabling them to diagnose performance problems with granular data. Furthermore, they track JavaScript errors through an internal application called Haystack, filtering out errors unrelated to their code. This approach encourages collaboration across teams, allowing seamless integration of front-end monitoring metrics with backend and network stats, and facilitates the easy addition of new metrics. While the current system provides valuable insights, GitHub aims to enhance their monitoring by integrating alert systems to promptly address front-end performance issues.