Alertmanager
The deduplication, grouping, and routing layer for Prometheus alerts. Sends to PagerDuty, Slack, email, webhooks.
Alerts
Grafana OnCall
Open-source on-call and incident-response — schedules, escalation policies, ChatOps. The closest OSS analog to PagerDuty.
Karma
Drop-in dashboard for Alertmanager — multi-cluster aggregation, richer grouping UI, on-call status, silence management.
Robusta
Kubernetes-native observability that turns Prometheus alerts into actionable, context-enriched events with auto-remediation playbooks.