Coding

online code running and testing

• https://repl.it/

Free code courses

• https://www.freecodecamp.org/
• https://www.codecademy.com/
• https://www.sololearn.com/
• https://www.theodinproject.com/
• https://www.codeschool.com (Partly)
• https://www.theodinproject.com/
• https://www.freecodecamp.com
• https://en.hexlet.io/

Exercises and challenges

• https://checkio.org/
• https://empireofcode.com/
• https://projecteuler.net/
• https://coderbyte.com/
• https://www.codewars.com/
• https://www.codingame.com
• https://edabit.com/challenges
• https://javascript30.com/
• https://medium.freecodecamp.org/6-absurd-ideas-for-building-your-first-web-application-24afca35e519
• https://www.fullstackacademy.com/student-gallery
• https://www.reddit.com/r/webdev/comments/3we48y/web_app_ideas_for_the_growing_web_developer/
• https://exercism.io/
• https://www.codechef.com/problems/easy/

HTML CSS

• https://developer.mozilla.org/en-US/docs/Learn/HTML
• http://flexboxfroggasdy.com/#nl
• https://css-tricks.com/the-css-box-model/

Databases

• https://www.pluralsight.com/blog/software-development/relational-non-relational-databases
• https://www.sitepoint.com/sql-vs-nosql-differences/
• https://university.mongodb.com/
• https://developer.mozilla.org/en-US/docs/Learn/Server-side/Express_Nodejs/mongoose
• https://blog.risingstack.com/node-js-database-tutorial/

Git

• https://lab.github.com/
• https://codeburst.io/number-one-piece-of-advice-for-new-developers-ddd08abc8bfa
• https://codeburst.io/a-step-by-step-guide-to-making-your-first-github-contribution-5302260a2940
• https://github.com/jlord/git-it-electron#readme
• http://ericsteinborn.com/github-for-cats/#/
• http://opensourcerer.diy.org/