PagerDuty is a tool used for managing on-call staff and setting alarms to escalate tickets through the appropriate channels. It can forward alerts from existing monitoring systems to PagerDuty, configuring on-call schedules and business rules for escalation, allowing team members to receive notifications such as SMS, email, or voice calls. This enables teams to stay informed about ticket status and take prompt action when necessary. Additionally, Twilio is integrated with PagerDuty, offering additional features like voice notifications that read aloud the contents of an alert, giving recipients the option to suppress or resolve a ticket.