J is a high-level, general-purpose programming language that is particularly suited to the mathematical, statistical, and logical analysis of data. It is a powerful tool for developing algorithms and exploring problems that are not already well understood.
J is written in portable C and is available for Windows, Linux, Mac, iOS, Android and Raspberry Pi. J can be installed and distributed for free. The source is provided under both commercial and GPL 3 licenses.
J is easy to install, has a small footprint, and has direct access to tutorials and documentation.
The latest release is J9.7 with several new language features and performance improvements, available from April 2026. See J9.7 Release Notes.
A J9.8 beta is available from April 2026.
Documentation can be found in the J wiki.
To download and install see Installation.
To build the J engine on your platform, see overview.txt. The various distributions for supported platforms are built with github actions.