freeCodeCamp is a nonprofit organization that consists of an interactive learning web platform that makes learning web development accessible to anyone.
CodePen is an ideal environment for educators to teach front-end design and development.
The DMOJ is a modern contest platform and archive of programming problems ideally geared towards High School computer science students.
CodeHS is a comprehensive teaching platform for helping schools teach computer science.
Apple’s new initiative “Everyone Can Code” brings the power of its programming language Swift, plus the just announced Swift Playgrounds, and great teaching materials – together, into a package that should help anyone learn how to code whether in or out of the classroom.