How to run a Python Flask project on Windows

What you need

• A Windows laptop.
• Python 3.12 or newer from python.org.
• Internet for the first run only, to download the packages the project uses.

The steps

1. Download Python from python.org and run the installer. On the first screen tick "Add python.exe to PATH" before you press Install. This is the step people miss.
2. Unzip your project and open its app folder.
3. Double-click run.bat. The first time, it prepares the project, installs the packages and creates the database with sample data. This takes a few minutes.
4. Your browser opens at http://127.0.0.1:5000. Sign in with one of the sample logins in your run instructions.

After the first run it starts in seconds and needs no internet.

Common problems

• "Python was not found": Python is not on the PATH. Run the installer again, choose Modify, and tick the PATH box, or reinstall with the box ticked.
• The install stops on school Wi-Fi: some networks block downloads. Do the first run at home or on your phone's hotspot, the night before.
• "Port 5000 is in use": the project is already running in another window. Close that window and try again.
• The window closes at once: open the app folder, type cmd in the address bar, press Enter, then type run.bat so you can read the message.

On defence day

Run it once before you leave home. At the venue, double-click run.bat, wait for the browser, and sign in. Keep the black window open while you present; closing it stops the system.