Manage on-call schedules and route alerts to the people handling incidents.
100% free open-source (AGPLv3) or free cloud tier (3 users).

Developer tools
Collect monitoring alerts, remove duplicates and coordinate incident responses.
Collect monitoring alerts, remove duplicates and coordinate incident responses.
Open-source AIOps, incident alerting, and workflow orchestration replacing $9-$29/user/mo paging tools.
Newer platform; advanced automated alert deduplication and correlation algorithms may require tuning alert mapping rules manually.
Each comparison covers the workflow described above, rather than every paid feature.