If you are completely new to web development, I HIGHLY RECOMMEND you visit these links first:
Roadmap to Web Development:
Mozilla Developer Network(MDN) Docs--(Highly Recommended)-- - everything you need to learn to develop web applications. Probably the only resource you'll need to learn web development. It also contains well organized guides to Django Web Framework, Express and Node.js.
w3schools - While this site is pretty decent for quick syntax lookup and reference, I --DO NOT-- recommend this over MDN to learn -how to program-. Before choosing w3schools over above resources, please go through this hackernews thread and this site by the mods of r/learnprogramming. This site also has references to Ajax, Node, PHP, SQL, XML, Java, Python, ASP, Angular, jQuery, Bootstrap, C++ and Raspberry Pi.
Deep Dive Into Modern Web Development - University of Helsinki - React, Node, Express, GraphQL
LambdaSchool Free Online Web Mini Bootcamp - HTML, CSS, JS
CodePen - Build, Test, and Discover Front-end Code
CodeSandbox - Online Code Editor Tailored for Web Application Development
Scrimba - Learn to Code with Interactive Tutorials
Box-shadow generator - This tool lets you construct CSS box-shadow effects, to add box shadow effects to your CSS objects.
Codrops - Web Dev and Design News.
HTML Reference - A free guide to HTML.
CSS Reference - A free visual guide to CSS.
Marksheet - A free HTML and CSS Tutorial.
Mozilla Grid Playground - Learn about CSS Grid Layout and the Firefox DevTools layout panel.
Flexbox Froggy - a simple 24 level game learn CSS flexbox.
Flexbox Defense - Learn CSS Flexbox by playing a tower defense game.
Grid Garden - Learn CSS Grid Layout by playing 28 different levels of Grid Garden.
Web Design in 4 minutes - Learn the basics of web design in 4 minutes with this interactive tutorial
CSS Gradient - free tool that lets you create a gradient background for websites and technical articles.
Official Python Docs - the official and easy to understand documentation of the Python programming language.
The Hitchhiker's Guide to Python - The best practice to installation, configuration and usage of Python on a daily basis.
Dive Into Python 3 by Mark Pilgrim.
Python Developer’s Guide - A comprehensive resource for contributing to Python.
GitHub/ See github-gitlab-stars.md/python
Overreacted - A blog by Dan Abramov
See More: Gist by Brad Traversy
JSONPlaceholder - Fake online REST API for developers
Fireship - Jeff from Fireship :)
Caleb Curry - Caleb Curry.
Clément Mihailescu - Clément Mihailescu.
Devhints - TL;DR for developer documentation
freeCodeCamp Guide - articles about all things related to programming.
Learn X in Y Minutes - quick reference sheets for the syntax of many different languages (generally not sufficient on their own for learning something, but very helpful)
GeeksforGeeks - A computer science portal for geeks
Cooperpress - Weekly email newsletters to developers and software engineers.