PagerDuty places a strong emphasis on reliability, deploying its code across multiple data centers and cloud providers to ensure uninterrupted alert services via phone, SMS, push notifications, and email. Despite their failure-tolerant design, implementation issues can arise, prompting the need for proactive strategies like the "Failure Friday" exercises. These weekly events involve intentionally introducing failures into their systems to uncover weaknesses, improve resilience, and enhance team collaboration. During these exercises, the team conducts a series of tests, such as stopping services, rebooting hosts, and simulating network issues, to evaluate and improve their systems' robustness. Communication is crucial during these sessions, with dedicated chat rooms and conference calls facilitating quick information exchange and logging actions for review. The insights gained are used to prevent future outages and reinforce PagerDuty's commitment to maintaining its high standards of reliability.