GitHub employs an internal exception tracking tool called Haystack to manage system and application-level issues, which range from Git timeouts to JavaScript errors. Developed over six years, Haystack helps monitor user-facing properties and desktop applications by detecting anomalies using simple rules like z-score calculations, setting exception thresholds, and providing real-time alerts via Hubot, which notifies engineers of potential issues following a deployment. This process involves analyzing exception rollups to identify trends, responsible parties, and affected areas. Haystack's integration with GitHub's systems and its Areas of Responsibility (AOR) framework assists in pinpointing the source and severity of issues. Despite its effectiveness, the deep integration and evolution of Haystack make it unsuitable for open-sourcing, although GitHub encourages others to adopt similar monitoring practices.