Monit vs PM2

Monit is a free, open-source utility for managing and monitoring Unix systems, available for Linux, macOS, and self-hosted deployment. It watches local daemon processes and can restart a stopped process or stop one using too many resources. It checks files, directories, and filesystems for timestamp, checksum, or size changes, and tests TCP, UDP, and Unix domain sockets using protocols such as HTTP and SMTP. Scheduled program or script checks can trigger actions or alerts based on exit values. Monit tracks CPU, memory, system load, and network interfaces, and sends customizable error alerts to syslog or its own log. Its HTTP(S) interface displays service status and allows process control and monitoring changes. It works with init, upstart, and systemd, can use existing run-level scripts, and can run as PID 1 in containers. The maker says it uses statically linked OpenSSL 3.5.7 and dynamically linked PAM support.

PM2 is a daemon process manager for managing applications and keeping them online. PM2 Runtime is an open-source process manager; PM2 Plus adds monitoring for Node.js production applications. Runtime supports cluster mode, zero-downtime reloads, watch and restart, startup scripts, log management and memory-based reloads. For containers, pm2-runtime can run Node.js applications with process fallback, flow control, monitoring and source-map support. PM2 Plus lists a web monitoring interface, application overview, issue tracking, custom metrics, server health checks and Node.js V8 monitoring. Its alerts include email and Slack notifications, while Enterprise adds rule-based alerting. The AI Assistant connects Claude, Cursor and other MCP-compatible assistants to monitoring data through OAuth with a PM2.io account. Documentation covers Docker, cloud providers, Heroku, AWS Elastic Beanstalk, Nginx and deployment workflows. Runtime costs nothing, and Plus costs $79 a month.