What is Flask (web framework) in Python?

What is Flask (web framework) in Python?

Have you ever wondered what Flask is and why it’s so popular in Python? Flask may be the appropriate solution for you if you’re seeking a lightweight web development framework. It is simple to use and comprehend, so you can get started designing web applications straight away.

Flask is a web framework that makes creating your own websites straightforward. In this post, we’ll define Flask and discuss some of the best things it has to offer! Are you ready to begin? Great! Let’s begin.

What is Flask?

Flask is a microframework for Python that encourages rapid development and clean code. It provides a simple, minimalist API that lets you write flexible and efficient web applications. It provides you with the tools you need to create an application quickly and easily, without having to deal with the complicated code that you usually have to write when you use other frameworks like Django or Ruby on Rails.

Basically, it helps you to create a website that has all the functionality that you need but without having to worry about writing the code yourself.

Flask allows you to create applications like this by handling all the complex back-end code for you. This makes it easy for you to just focus on building your application, rather than having to learn a bunch of complex coding skills to get everything working!

flask web

Flask also has the benefit of being incredibly lightweight and simple to use. Flask is based on Werkzeug, making it highly lightweight and easy to deploy. This means that you can run your web application on a local server for testing purposes without having to deal with the hassle of deploying to production servers every time you want to test something out.

This makes developing your application really simple and convenient! There are plenty of other options available when constructing a web application with Flask. For example, you can use it to set up databases and create web services to communicate with your server over HTTP!

How do I begin using Flask?

Overall, Flask is a fantastic framework for developing web apps in Python, and you should absolutely give it a shot if you want to learn how to build your own! Interested in getting started?

Flask is a sophisticated Python web development framework for creating dynamic, interactive web pages. In this article, we’ll teach you how to use the Flask web development template to construct a basic Flask application. Then, we’ll cover how to install and use the Flask command line tool to start developing your applications

Setting up a development environment and installing Flask

This guide will walk you through the process of setting up a Flask development environment and installing it.

This environment will include both the Flask web application development framework and the Python programming language.


Installing Flask and Python is a simple process on most systems, but the process may vary slightly depending on your system.

Before you can begin developing applications with Flask, you will need to set up a development environment that will enable you to create and deploy new web applications. The following instructions will help you do just that.

Install Python on your system

We will use Python 3. X version in this guide because it is the most recent release and supports all of the latest features of Flask.

To ensure that you have the proper version of Python installed on your computer, follow these steps:

Navigate to the Python website and download the installer for your system. Choosing the right version from the drop-down menu after clicking the Download button and continuing after clicking it.

The installer will automatically download and begin running. During the installation process, you may need to agree to an End User License Agreement and click Accept to continue the installation.

When the installation is complete, you should see a window that says “Python X.X.X Installed Successfully” with a green checkmark box next to “Is this OK?” Click OK to exit out of the installer window. You can now use Python to perform basic operations like running scripts and opening files.

Install virtualenv

Virtualenv is a tool that allows you to install multiple versions of Python and other popular programming tools on a single computer. It enables you to build separate contexts for every program, which lessens conflicts and streamlines development.

Enter the following command in your terminal window to generate virtual environments for your program:

$ pip install virtualenv
Code language: Bash (bash)

Create a virtual environment for Flask

In your terminal window, navigate to the directory where your web application project is located and run the following command to create a virtual environment for your project:

$ virtualenv env name -of-environment
Code language: Bash (bash)

Here, env is the name of the virtual environment that you just created. The name value is optional but makes it easier to identify the virtual environment in the future. For example, you might want to name it flask or python-flask or something similar.

If you enter a different name than flask or python-flask, you will need to specify this name when using the commands that we will create later.

A popup stating “new env ‘env’ activated” will appear after the virtual environment has been created. Now that you’ve used the Escape key on your keyboard, you may shut the window.

You will need to repeat this step for each virtual environment that you will create for this project.

Now that we have created a virtual environment, let’s install the Flask framework into it so that we can use it for our project.

In your terminal window, type the following command to install the Flask framework into the virtual environment you just created:

$ source env/bin/activate
Code language: Bash (bash)

Once you have done this, you should be able to run the command pip freeze to verify that the Flask framework has been installed correctly into your virtual environment.

Next, let’s create a folder called static in our web application project’s root directory for storing static files like images and text files.

Run the following command to do this:

$ mkdir static $ cd static
Code language: Bash (bash)

Developing our first Flask application

In this tutorial, we will be creating a simple Flask app using Python. We will be using the Flask microframework to create our app.

To begin, we will install the Flask microframework.

Launch a command prompt and enter the following:

$ pip install flask
Code language: Bash (bash)

Once the installation has finished, we can use the Flask command line interface to create a new project.

To do this, we’ll employ the create command as seen below:

$flask create my_first_app
Code language: Bash (bash)

This will create a new directory called my_first_app in the project’s directory. The newly created directory will contain a file called app.py which will hold the main code for our application.

The following code will also be present in the app.py file:

from flask import Flask app = Flask(__name__) @app.route("/") def home(): res = "Hello world!" return res if __name__ == "__main__": app.run(host='', port=80)
Code language: Python (python)

A piece of code that is executed when the application is run. In this case, we simply display a message on the screen.

To load this app into a web browser, we use the following command:

$flask serve
Code language: Bash (bash)

This will start the server and display the app in the web browser at http://localhost:5000/. Finally, we can modify the code to display a different message.

web browser1

For example, we could change the line containing ‘Hello world!’ to ‘Hello, World!’ and display this new message in the browser.

To do this, we would simply open the file and change the line as follows:

from flask import Flask app = Flask(__name__) @app.route("/") def home(): res = "Hello, World!" return res if __name__ == "__main__": app.run(host='', port=80)
Code language: Python (python)

Restarting the server or reloading the page in the browser will load the new version of the application and display the message ‘Hello , World!’ instead of ‘Hello world!’ In our example, we loaded an existing project and created a very simple web application using Flask.

web browser

You should now be able to create more complex web applications with the Flask framework. For more information on Flask and other web development frameworks, check out our web development tutorials page.

Finally, This code generates a new Flask app called my_first_flask. It then defines a route called, which will reply to a request with a “Hello World!” message.

Finally, the code runs the app in development mode so that you can see the results in your terminal window as the application is running.

Save the changes to my_first_flask.py and run the following command to run the application: python my_first_flask.py

You should see output like this in your terminal window. Congratulations! You’ve written your first Flask application!

You can download the official Flask documentation here. Cheers!

Best features of Flask

Flask is a powerful Python microframework that helps you develop web applications quickly and easily. Here are the best features of Flask that make it a great choice for web development:

Ease of Use and Quick Development

Flask is designed to be easy to use and quick to develop. You can begin developing your app with just a few lines of code. However, the advanced features of Flask make it a good choice for more experienced developers as well.

Friendly Ecosystem

The Flask ecosystem has a ton of great tools that you can use in your projects. For example, the built-in debugging features make development easier and error reporting more accurate.


Seamless Integration with Other Technologies

The Flask extension system allows you to integrate your app with other popular tools and services. This feature allows you to create feature-rich web apps without the need for complex integrations with external systems.

Highly Customizable

Flask is highly customizable, so you can modify and extend the framework to fit your specific project needs. In addition, there are several third-party libraries and frameworks that you can use to enhance the framework’s functionality even further


Flask is a web framework written in Python. It is a microframework that simply provides the essential building blocks needed to develop a web application. This includes routing, request and response objects, and template rendering. Flask is easy to use and is a great choice for small projects. Thanks for reading!!

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