Windows
In PowerShell:
py -m pip install cptr
cptr runYour browser opens at http://localhost:8000. If cptr is not recognized after installing, Python's Scripts directory isn't on PATH. Reopen PowerShell after adding it, or install into a virtual environment and run cptr from there.
Terminal fails with a missing VCRUNTIME140.dll
If opening a terminal reports a missing VCRUNTIME140.dll or Universal CRT DLL, install Microsoft's Visual C++ Redistributable, then restart cptr.
Which account should run it
Open WebUI Computer runs with the rights of the Windows account that starts it; that account's permissions decide what the file browser and terminal can reach. Use your normal account; don't run it as administrator just to make a folder easier to reach.
Keep it running
To have Open WebUI Computer start automatically and survive logouts, see keep it running.