Free Code Camp - Learn to code by helping nonprofits.
CodeAbbey - Programming problems to practice and learn for beginners
W3Schools - W3Schools is a web developers information website, with tutorials and references on web development...
Coderbyte - Coderbyte is a place built for anyone to practice and perfect their programming skills.
Codecademy - Learn the technical skills you need for the job you want. As leaders in online education and learning to code, we’ve taught over 45 million people using a tested curriculum and an interactive learning environment.
Codewars - Achieve code mastery through challenge.