Deploy Flask App on Heroku

mkdir app

cd app

app.py

from flask import Flask, jsonify, request

app = Flask(__name__)

@app.route("/")
def index():
    return "Hello World!"

@app.route('/add')
def add():
    num1 = int(request.args.get('num1'));
    num2 = int(request.args.get('num2'));

    return f"{num1} + {num2} = {num1 + num2}"

#if __name__ == "__main__":
    #app.run(debug=True);
    #app.run(host="0.0.0.0", port=int("1234"), debug=True)

runtime.txt

python-3.10.8

Procfile

web: gunicorn app:app

requirements.txt

click==8.0.3
colorama==0.4.4
Flask==2.0.2
Flask-Cors==3.0.10
gunicorn==20.1.0
itsdangerous==2.0.1
Jinja2==3.0.3
MarkupSafe==2.0.1
PyMySQL==1.0.2
six==1.16.0
Werkzeug==2.0.2

OR

You can output all dependencies using following command

python -m pip freeze > requirements.txt

heroku login

#onetime
heroku create <appname>
heroku git:remote -a <appname>
git init

#repeat whenever you make changes
git add .
git commit -m 'heroku push'
git push heroku master

Test API

https://myflaskapp2022.herokuapp.com/
https://myflaskapp2022.herokuapp.com/add?num1=5&num2=9

Troubleshoot

heroku logs --tail --app eflask-app-dusra

If still it is not working please do check spellings of files

https://devcenter.heroku.com/articles/buildpacks