Flask Python Tutorial: What It is and How to Install

Jinja2 is a web template engine that combines a template with a certain data source to render dynamic web pages. In Easy Language, It combines a template (the layout of the page) with data (the specific information you want to show) to create a dynamic web page. Flask is a web framework that allows developers to build lightweight web applications quickly and easily with Flask Libraries. It was developed by Armin Ronacher, leader of the International Group of Python Enthusiasts(POCCO). It is basically based on the WSGI toolkit and Jinja2 templating engine. Virtual environments are independent groups of Python libraries, one for each

flask framework in python

You can make parts of the URL dynamic and attach multiple
rules to a function. It is
omitted in most examples for brevity, but you should always be aware of
how you’re using untrusted data. This launches flask developer a very simple builtin server, which is good enough for
testing but probably not what you want to use in production. The color scheme for the links provides a visual cue to users about clickable elements.

Save and close the file, then create a new edit.html template:

You start by declaring the doctype, wrapping everything in tags, and setting the lang attribute. Over the course of this tutorial, you’ll explore the process of creating a boilerplate for a Flask web project. This boilerplate will serve as a great starting point for any scalable Flask web app that you wish to develop in the future, from basic web pages to complex web applications. Flask is a powerful and flexible micro web framework for Python, ideal for both small and large web projects.

The rest of the docs describe each
component of Flask in detail, with a full reference in the API
section. The above code shows “Hello, World!” on localhost port 5000 in a web browser
when run with the python app.py command and the Flask library installed. Stop the development server in your other terminal that runs the hello application with CTRL+C. In this step, you’ll create your main Flask application in a new file. Now you’ll install Python packages and isolate your project code away from the main Python system installation.

Step 4 — Routes and View Functions

If you are using Git, it is a good idea to ignore the newly created env directory in your .gitignore file to avoid tracking files not related to the project. In this step, you’ll activate your Python environment and install Flask using the pip package installer. It’s a very valuable skill https://remotemode.net/ if you’re hoping to land a developer position. Full stack developers are in high demand because of their ability to contribute across the board. This is a great opportunity to further explore both sides of development, which in turn can make you a more generously compensated developer.

Using this information, we will now start building a real-world application. With some minimal styling, your Flask web project is starting to look like a finished web app. Once you’re finished, you can continue to work on the message board project by adding a database and accepting posts from your users. Armin Ronacher, who leads an international group of Python enthusiasts named Pocco, develops it. Flask is based on Werkzeug WSGI toolkit and Jinja2 template engine. It doesn’t require you to use any particular project
or code layout.


The application we’ll be building is an animal rescue website called “Paws Rescue Center”. Let’s start to create an application with a Home page and About page. Flask offers suggestions, but doesn’t enforce any dependencies or
project layout.

  • You then use it to create your Flask application instance with the name app.
  • If you’d like to get started on your first project in Flask, you can visit here.
  • However, we suggest using python 3 for the development in the flask.
  • There are many serialization libraries and Flask API extensions
    maintained by the community that support more complex applications.
  • Then, you define two routes, one as the home view and the other as the about view.