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PM2

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by Keymetrics (Unitech) · CLI tool · also known as pm2, PM2 Process Manager

Production process manager for Node.js and other long-running programs with cluster mode, log handling, restart policies and boot-time startup scripts

AGPL-3.0-only licenseOpen sourceFreePaidSelf-hostedLocalSelf-hostable
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Link verified Nov 2, 2026

Overview

PM2 is an open-source process manager, published by Keymetrics under the AGPL-3.0 license, that keeps server applications running: it starts them, restarts them on crash or memory limit, rotates and tails their logs, and generates startup scripts so processes return after a reboot. Although written for Node.js, it supervises any executable, including Python, shell and binary programs, through its ecosystem configuration file.

Its distinctive feature is cluster mode, which forks a Node.js application across all CPU cores behind a shared port and allows zero-downtime reloads. An ecosystem file (JavaScript, JSON or YAML) declares every process with environment variables, working directory, instance count and log paths, so a server's full set of services can be versioned and brought up with a single pm2 start. The pm2 startup command writes a systemd or launchd unit, and pm2 save persists the current process list. A companion SaaS, PM2 Plus and PM2 Enterprise at pm2.io, adds remote monitoring and metrics on a subscription basis; the CLI itself needs no account.

PM2 suits small and medium deployments where a handful of services run directly on a host rather than inside containers, which is common on VPSs and in homelab or Mac-mini clusters. It does not isolate processes, manage dependencies or schedule across machines; those jobs belong to containers or an orchestrator. The AGPL license and the Node.js runtime requirement are worth noting for redistribution and minimal servers.

Capabilities

  • Supervise and auto-restart processes with crash, memory and cron-based policies
  • Cluster mode that load-balances a Node.js app across CPU cores with zero-downtime reload
  • Ecosystem configuration file describing many processes and environments
  • Log aggregation, rotation (module) and real-time tailing
  • Startup script generation for systemd, launchd and other init systems
  • Deployment helper for pulling and restarting from a git remote
  • Optional remote monitoring through PM2 Plus

Typical workflows

  1. Keep several web services alive on one Linux or macOS host
  2. Reload a Node.js API across cores without dropping connections
  3. Register all services so they return automatically after a reboot
  4. Tail and rotate logs for a fleet of scripts

Strengths

  • Very small learning curve for Node.js developers
  • Runs on macOS and Linux without containers
  • Single file describes an entire host's processes
  • Mature project with long release history

Limitations

  • AGPL-3.0 license has obligations for modified redistributions
  • No isolation or dependency management between processes
  • Single-host only; no scheduling across machines
  • Requires a Node.js runtime even for non-Node programs

Prerequisites

  • Node.js runtime
  • Shell access to the host

Who it is for

  • Node.js developers
  • Operators of small VPS or on-premises fleets
  • Researchers running long-lived services on workstations

Alternatives & comparison

launchd (macOS) and systemd (Linux) are the native supervisors and need no runtime, but lack cluster mode, unified logs and a cross-platform CLI. Docker restart policies supervise containers rather than bare processes and add isolation at the cost of an image build step. Kubernetes handles the same restart and scaling concerns across a cluster and is the step up once services span many hosts.

  • Docker

    Container platform combining the Docker Engine runtime, the Compose and Build tooling, Docker Desktop for macOS and Windows, and the Docker Hub registry

    MixedOpen source
  • Kubernetes

    Open-source system for scheduling, scaling and operating containerized workloads across a cluster of machines

    Open sourceOpen source
  • launchd

    macOS's built-in service manager that starts, supervises and schedules daemons and per-user agents from property-list job definitions

    ProprietaryFree
Compare PM2 with its alternatives →

Sources & verification

Primary sources consulted for this record. Claims are tied to the fields each source supports; the automated link checker re-verifies every URL on a schedule.

  • License
    PM2 license (GNU AGPL-3.0)

    https://github.com/Unitech/pm2/blob/master/GNU-AGPL-3.0.txt

    Supports: license_spdx, source_model

    checked Nov 1, 2026
  • Official documentation
    PM2 Quick Start

    https://pm2.keymetrics.io/docs/usage/quick-start

    Supports: capabilities, workflows, prerequisites

    checked Nov 1, 2026
  • Official site
    PM2 - Advanced Production Process Manager for Node.js

    https://pm2.keymetrics.io/

    Supports: name, summary, capabilities

    checked Nov 1, 2026
  • Pricing page
    PM2 Plus pricing

    https://pm2.io/pricing

    Supports: pricing_model

    Pricing concerns the optional PM2 Plus/Enterprise monitoring service, not the CLI.

    checked Nov 1, 2026
Confidence
High
Reviewed
Nov 1, 2026
Links
Verified · Nov 2, 2026

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