How to Setup a New Flask App on a Mac

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Welcome back internet friend!

Quick post here tonight on how to setup a new flask app for development on a Mac. In the past I’ve done all of my Python/Flask development on a Windows desktop computer, but since I’m now doing all of my development on a Macbook Pro, I wanted to write another little quickstart reference for myself or anyone else out there on the internet to get up and running with Python and Flask on a Mac (assumes you’ve already installed Python 3, if you haven’t, please visit

First, make sure virtualenv is installed

$ pip3 install virtualenv

Then create a directory for your new Flask project

$ mkdir MyNewFlaskApp

Navigate to your newly created directory

$ cd MyNewFlaskApp

Create your virtual environment

$ virtualenv venv --system-site-packages

Activate the virtual environment

$ source venv/bin/activate

Make sure Flask is installed

(venv) $ pip3 install Flask

Now write the actual python code for your flask application. We’ll call our python script Save this script in your MyNewFlaskApp directory.

from flask import Flask
app = Flask(__name__)
def index():
return 'hello, world'
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Set the FLASK_APP system variable

(venv) $ export

Run Flask

(venv) $ flask run

Visit to see your app in action