Setting the Flask ENV Variable

This post covers how to set the FLASK_APP environment variable to run Flask.

[01] Setting FLASK_APP

• When you run flask run, Flask looks for app.py or wsgi.py in the current directory and starts the server.
• If you renamed those files, you must set FLASK_APP=<filename> for it to run correctly.

When the file is named test.py:

# Linux
export FLASK_APP=test

# PowerShell (Windows 10, VSCode)
$env:FLASK_APP="test.py"

# Bash shell (Windows 10, VSCode)
set FLASK_APP=test