Running a Node.js Daemon with Fastify (No PM2, No systemd)

Every few months someone on Reddit asks "how do I run a Node.js process in the background." The answers are always PM2, forever, or systemd. All fine. But if you're shipping a CLI tool that users install on their own machines, you can't assume any of those exist. I have a CLI that starts a local HTTP daemon. my-tool start forks into the background, user closes their terminal, daemon keeps running. About 700 lines for the whole thing, 150 of which are just the fork/PID/signal plumbing. Fastify 5 for the HTTP layer. Fork, detach, forget import { fork } from " node:child_process " ; import * as fs from " node:fs " ; import * as path from " node:path " ; import * as os from " node:os " ; const DATA_DIR = path . join ( os . homedir (), " .my-tool " ); const LOG_PATH = path . join ( DATA_DIR , " daemon.log " ); function startDaemon (): void { fs . mkdirSync ( DATA_DIR , { recursive : true }); const logFd = fs . openSync ( LOG_PATH , " a " ); const child = fork ( __filename , [ " start " , "