We currently support 13 different languages. C# (14th) is disabled pending additional player interest (beer for admins).
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Our core supported languages are colored in green. The rest of the languages, colored in blue, are supported as well but have not been as thoroughly tested against the challenges on our site. As such, we cannot guarantee that all necessary third-party libraries required to solve every challenge are installed. This is where we rely on you, the users, to provide us with feedback if you feel one was omitted and should be included.

BASH

The Bourne-Again Shell

C

The C Programming Language

C++

The C++ Programming Language (originally C with Classes)

C#

This is currently disabled. We might enable support if there is enough player interest.

The C# Programming Language (we compile in Windows/.NET)

Go/Golang 1.9.2

compiled, conncurrent, imperative, structured

Haskell

Purely Functional, lazy/non-strict, modular

Lisp

Common Lisp; functional, procedural, reflective, meta; fully parenthesized prefix notation.

nodejs 9.2.0

JavaScript runtime environment using Google's V8 engine

Python 2.7.12

General-Purpose Scripting Language

Python 3.6.3

General-Purpose Scripting Language

PHP 7.1.11

Server-Side Scripting Language (primarily used for the web but also for general-purpose)

Perl 5.22.1

A high-level, general-purpose, interpreted, dynamic programming language

Ruby

A dynamic, reflective, object-oriented, general-purpose programming language

Rust

A systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.

Scala

A general-purpose programming language providing support for functional programming and a strong static type system