PM2 is a production process manager for Node.js applications with built-in load balancing, monitoring, and deployment capabilities. It keeps applications alive forever, enables zero-downtime reloads, and provides comprehensive system administration features. The architecture features a daemon-based design with CLI and programmatic APIs communicating via IPC (pm2-axon). Key capabilities include process clustering, log management, metrics collection, Docker integration, startup script generation, and a plugin system for extensibility. The codebase demonstrates strong engineering practices with internalized dependencies to reduce supply chain risk, comprehensive test coverage, and active maintenance with regular updates supporting Node.js >=18 and Bun.