For questions about the Japt language. Note that challenges that require the answers to be in a specific language are generally discouraged.

Japt is a shortened version of JavaScript, created by ETHproductions in early November 2015.

The online interpreter can be found at and the GitHub project at

Japt is heavily based off of JavaScript. After transpiling Japt's syntax features to JavaScript, it is evaluated as vanilla JS. This allows easy building of an online interpreter. Some of the main features are:

  • One-letter functions: each lowercase letter corresponds to a specific function, which is different on strings, arrays, and numbers.
  • String compression: Japt uses the shoco library for string compression. Wrapping a string in backticks tells the interpreter to automatically decompress it.
  • Anonymous functions: XY{X+Y} is transpiled to function(X,Y){return X+Y}, as is @X+Y}, and in some cases, simply +. This allows for easy creation of functions on the fly.
  • Unicode shortcuts: All 1-byte characters from ¡ to Ì transpile to longer sequences of chars.
history | excerpt history