Alloy

Alloy is an open‑source language and analyzer designed for software modeling. It provides a formal notation for describing system structures and behaviors, together with a model‑finding engine (Kodkod) that can automatically search for instances or counterexamples. The platform includes a visualizer for exploring analysis results and supports extensions built by the community.

The language is used in diverse domains such as security analysis and network design, where precise specifications help uncover flaws or verify properties. Alloy 6, the current major release, introduces mutable state, a temporal logic, and dedicated solvers, simplifying the expression of dynamic system behavior compared with earlier versions. The release also updates the syntax and improves the visualizer.

Documentation, tool downloads, case‑study links, and a draft online guide for practical Alloy are available on the project site. The software runs on macOS as a stable, core component, and the community maintains extensions and additional tools built on top of the Analyzer and its underlying engine.