Percy is a visual testing and monitoring tool that focuses on detecting visual changes in web applications

Uptime Kuma is an easy-to-use self-hosted monitoring tool.

Datadog is a cloud-based monitoring and analytics platform that provides observability and security for cloud-scale applications

Status, performance and uptime monitoring for cron jobs, websites, APIs and more.

LangSmith Observability gives you complete visibility into agent behavior with tracing, real-time monitoring, alerting, and high-level insights into usage.

Vigil is an open-source Status Page you can host on your infrastructure, used to monitor all your servers and apps, and visible to your users.