The best free alternative to Coderbyte is freeCodeCamp, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 50 alternatives to Coderbyte and loads of them is free so hopefully you can find a suitable replacement. Other interesting free alternatives to Coderbyte are Codecademy (Freemium), Coursera (Freemium), SoloLearn (Freemium) and W3Schools (Free).
InterviewBit gamifies the experience of practicing for your interview and includes lots of sample problems. The problems have been categorized into topics and then micro-concepts within topics. Each problems have hints and editorials with them.
Online programming language courses, just like w3schools.com. It also includes a "Try it yourself" editor so that people can try their web designing source code in a browser, without downloading anything on their computer.
Stop wasting your engineers' time with candidates you never hire. Paircast video take-homes show you how candidates solve real-world problems before they reach your engineers. Records screen and code changes during development. Works with all languages.