Keep a Python script running in the background on Windows

A Python script run from a console window stops when you close that window. The usual Windows fixes are pythonw.exe (the same interpreter without a console window, so output goes nowhere), Start-Process pythonw -ArgumentList worker.py to launch it detached, or a scheduled task for something that should run at login or on a timer. Each leaves you to find the process in Task Manager when you want it gone.

The Moonpool way

Moonpool runs the command in its own terminal tab, so you keep the output and a Stop button without a console window of your own. For a script that runs until you stop it, use a cli app. -u makes Python flush output right away so the tab shows it live:

apps.json

{
  "id": "worker",
  "name": "Queue worker",
  "group": "Scripts",
  "type": "cli",
  "cwd": "C:\\code\\worker",
  "command": ".venv\\Scripts\\python.exe -u worker.py"
}

Launch it and click the app’s name to watch its output. A cli app counts as Running while its command runs, and goes grey when the script exits, with [process exited] left in the tab. Stop ends the script and anything it started. Using the virtual environment’s python.exe by path means no activation step is needed.

If the script serves HTTP (Flask, FastAPI, python -m http.server), make it a web app so Running follows its port:

apps.json

{
  "id": "docs-api",
  "name": "Docs API",
  "group": "Scripts",
  "type": "web",
  "cwd": "C:\\code\\docs-api",
  "command": ".venv\\Scripts\\python.exe -u app.py",
  "port": 8091,
  "url": "http://127.0.0.1:8091",
  "env": { "PORT": "8091" }
}

Limits

• Keep Moonpool running. Closing its window quits it by default, and on Windows quitting stops every app it launched. Turn on Close to tray to hide the window instead; see Tray, close and minimize.
• Moonpool does not restart a script that crashes, and does not start it at Windows login by itself. See Start a script or dev server automatically at Windows login.
• Avoid nested double quotes in command: the cmd /c wrapper mangles them.

See also

• App types: how cli and web apps are tracked.
• Stop and restart
• Examples
• Logs: where session output is kept.