How to Deploy a Flask app online using Pythonanywhere – 2023

Machine Learning Projects

In today’s blog, we are going to Deploy a Flask app online using Pythonanywhere. The app we are going to deploy will be a sketch-making Flask app that we created in the previous blog.

This is going to be a very interesting project because learning how to deploy an app online is a very important skill nowadays. So without any further due, let’s do it…

Check the video tutorial here –

Snapshot of our Final app…

Deploy a Flask app online

Step 1 – Create an account on Pythonanywhere.

  • When you create an account on Pythonanywhere and log in for the first time, your screen will look like this.
  • Notice no apps under Web apps.
Deploy a Flask app online

Step 2 – Create a Web App

  • Click on the Web in the Header Menu.
Deploy a Flask app online
  • Click on Add a new web app.
Deploy a Flask app online
  • Click on Next.
  • Select Flask on the Next Screen.
  • Then Select the Python version you want to work in. I selected Python 3.9 & Flask 2.0.0.
Deploy a Flask app online
  • Here change to (I will be uploading my Flask file with the name, you can change it according to your file name) and click on Next.

Step 3 – Upload the required files.

  • Now click on the Files section in Header Menu.
  • You will see a mysite folder there.
  • This is the folder in which we need to place all our files.
Deploy a Flask app online
  • Upload the file in mysite folder.
  • Create an empty folder static. Now create one more empty folder called uploads in the static folder.
  • Create empty folder templates.
  • Upload home.html in the templates folder.
  • Download home.html and
Deploy a Flask app online

Step 4 – Let’s run the app

  • Now again go on the Web and hit the green Reload button.
  • And now your website should be good to run online.
Deploy a Flask app online

Step 5 – Let’s check our App online

Deploy a Flask app online

Final Sketch Results…

Deploy a Flask app online

Source codes for your reference…

import cv2
import os
from werkzeug.utils import secure_filename
from flask import Flask,request,render_template

UPLOAD_FOLDER = 'mysite/static/uploads'
ALLOWED_EXTENSIONS = set(['png', 'jpg', 'jpeg'])

app = Flask(__name__)
app.config['SEND_FILE_MAX_AGE_DEFAULT'] = 0
app.secret_key = "secret key"

def allowed_file(filename):
    return '.' in filename and filename.rsplit('.', 1)[1] in ALLOWED_EXTENSIONS

def make_sketch(img):
    grayed = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    inverted = cv2.bitwise_not(grayed)
    blurred = cv2.GaussianBlur(inverted, (19, 19), sigmaX=0, sigmaY=0)
    final_result = cv2.divide(grayed, 255 - blurred, scale=256)
    return final_result

def home():
    return render_template('home.html')

def sketch():
    file = request.files['file']
    if file and allowed_file(file.filename):
        filename = secure_filename(file.filename)['UPLOAD_FOLDER'], filename))
        img = cv2.imread(UPLOAD_FOLDER+'/'+filename)
        sketch_img = make_sketch(img)
        sketch_img_name = filename.split('.')[0]+"_sketch.jpg"
        _ = cv2.imwrite(UPLOAD_FOLDER+'/'+sketch_img_name, sketch_img)
        return render_template('home.html',org_img_name=filename,sketch_img_name=sketch_img_name)

if __name__ == '__main__':


<!doctype html>
<html lang="en">

<style type='text/css'>
    body {
        font-family: sans-serif;
        margin-top: 40px;

    .regform {
        width: 800px;
        background-color: rgb(0, 0, 0, 0.8);
        margin: auto;
        color: #FFFFFF;
        padding: 10px 0px 10px 0px;
        text-align: center;
        border-radius: 15px 15px 0px 0px;


    .main-form {
        width: 800px;
        margin: auto;
        background-color: rgb(0, 0, 0, 0.7);
        padding-left: 50px;
        padding-right: 50px;
        padding-bottom: 20px;
        color: #FFFFFF;

    img {
        max-height: 400px;
        max-width: 500px;
        height: auto;
        width: auto;

    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">

    <!-- Bootstrap CSS -->
    <link href="" rel="stylesheet"
        integrity="sha384-eOJMYsd53ii+scO/bJGFsiCZc+5NDVN2yr8+0RDqr0Ql0h+rP48ckxlpbzKgwra6" crossorigin="anonymous">



    <div class='regform mt-3'>

    <form action='/sketch' class='main-form' method="POST" enctype="multipart/form-data">

        <div class='text-center'>
            <input type="file" id="file" name='file' style="margin-top:10px;margin-bottom:10px;">
            <button type='submit' class='btn btn-outline-success'> Make Sketch


    {% if sketch_img_name %}
    <div class="row" style="margin-top:10px;margin-bottom:10px;">
        <div class="col text-center">
            <h2>Original Image</h2><img src='../static/uploads/{{ org_img_name }}'
                style="display: block;margin-left: auto;margin-right: auto;">
        <div class="col text-center">
            <h2>Sketch Image</h2><img src='../static/uploads/{{ sketch_img_name }}'
                style="display: block;margin-left: auto;margin-right: auto;">
    {% endif %}



And this is how you Deploy a Flask app online…

So this is all for this blog folks. Thanks for reading it and I hope you are taking something with you after reading this and till the next time …

Read my previous post: Best way to Explore Data using Interactive EDA Reports in Python

Check out my other machine learning projectsdeep learning projectscomputer vision projectsNLP projects, and Flask projects at

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