At CodinGame, our goal is to let programmers keep on improving their coding skills by solving the World's most challenging problems, learn new concepts, and get inspired by the best developers.

Another online learning community. Like Codewars, the IDE is in the browser.

You get mission statements and then have to write code to fulfill the requirements thereof.

Solo and multiplayer coding games are turn-based: at each turn, your program gets new inputs and must output the action.

Supported languages:
C# C++ Java Javascript Python3 Bash C Clojure D Dart F# Go Groovy Haskell Kotlin Lua ObjectiveC OCaml Pascal Perl PHP Ruby Rust Scala Swift TypeScript VB.NET

Sadly, no Fortran or COBOL. (Sigh)