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Codecademy is the easiest way to learn how to code. It's interactive, fun, and you can do it with your friends.

Free Code Camp's open source community help you build a job-worthy portfolio of real apps used by real people, while helping nonprofits.

Code School teaches web technologies in the comfort of your browser with video lessons, coding challenges, and screencasts.

A fun social platform for hackers to solve interesting puzzles, build quick hacks, code game bots and collaborate to solve real-world challenges.

Project Euler is a series of challenging mathematical/computer programming problems that will require more than just mathematical insights to solve. Although mathematics will help you arrive at elegant and efficient methods, the use of a computer and programming skills will be required to solve most problems.

Are you a code newbie?

Duel with friends and foes in head-to-head programming battles!

Coderbyte is a place built for anyone to practice and perfect their programming skills. Challenges are added almost every day so you can work on applying your algorithmic thought process on any problem you want at anytime. Coderbyte is built on improving your ability to work on common logic, mathematical, and algorithmic problems you might one day encounter.

CodinGame is a challenge-based training platform for programmers where you can play with the hottest programming topics.

Teaching technology via app development.Learn By Doing :We believe that the best way to learn a language is to attempt building something on it. With tests to check your progress, our courses help you learn while coding.

CheckiO is expanding the world’s code literacy through gameplay.

Achieve code mastery through challenge.Improve your skills by training with others on real code challenges

A platform for creating and learning to create innovative products

CodeChef was created by Directi as a way to continuously challenge and engage the developer community. Our goals are to provide a platform for practice, competition and improvement as well as enable developers to benchmark their skills against their peers. We’re having fun with the site and hope you will too.

Topcoder gathers the world’s experts in design, development and data science to work on interesting and challenging problems. Members are provided with opportunities to demonstrate their expertise, improve their skills, and win cash, while helping real world organizations solve real world problems.