Alloy Analyzer
Alloy Analyzer explores models written in the Alloy language, searching for structures that satisfy constraints or counterexamples to properties.
What Alloy Analyzer is
Alloy Analyzer explores models written in the Alloy language, searching for structures that satisfy constraints or counterexamples to properties. Alloy models can represent sets of structures that change over time, such as security configurations or switching network topologies. The Analyzer displays structures graphically, and their appearance can be tailored to a domain. Alloy 6 adds mutable state, temporal logic, and temporal model checking; the model checking requires NuSMV or nuXmv installed by the user and available in PATH. Its self-contained executable includes the Pardinus/Kodkod model finder, SAT solvers, the standard Alloy library, tutorial examples, and source code. The same JAR can be embedded in other applications as an API. Sterling is a web-based visualizer with graph and table views, customizable and extendable with JavaScript. Alloy is a free, self-hosted project available for Linux, macOS, and Windows. It supports invariant verification and counterexample generation, and the project lists Alloy 6.2.0 as its latest release, dated 2025-01-09.
Good
- Free, self-hosted, and available on Linux, macOS, and Windows.
- Finds structures and counterexamples in Alloy models.
- Executable bundles model finder, SAT solvers, library, examples, and source.
- Sterling provides graph and table visualizations.
Watch out
- Temporal model checking requires user-installed NuSMV or nuXmv.
- Project is maintained by volunteers.
Who it suits
Alloy Analyzer suits people modeling systems and checking whether structures meet constraints or properties hold. It can also fit developers embedding Alloy through its JAR API or users who want graphical model views.
Verdict
Alloy Analyzer combines constraint-based model exploration with graphical presentation and counterexample discovery. Its temporal checking has an external dependency, but the executable bundles core components and examples for local use.
Plans and prices
From Alloy Analyzer's own pricing page, checked 4 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Alloy Analyzer | Free | Open source project · self-contained executable |
The facts
Each one read from Alloy Analyzer's own pages, with the date it was checked.
What it does
- API
- The same JAR file can be incorporated into other applications to use Alloy as an API.checked 4 Oct 2026
- Bundled components
- The self-contained executable includes the Pardinus/Kodkod model finder, SAT solvers, the standard Alloy library, tutorial examples, and source code.checked 4 Oct 2026
- Community support
- The project is maintained by volunteers, with Discourse as its main discussion venue and Stack Overflow as the venue for precise questions monitored by developers.checked 4 Oct 2026
- Modeling
- Alloy models describe sets of structures that may evolve over time, such as security configurations or switching network topologies.checked 4 Oct 2026
- Origin
- Alloy was created in MIT's Software Design Group.checked 4 Oct 2026
- Purpose
- Alloy is a language for describing evolving structures, and the Alloy Analyzer explores models by finding structures that satisfy constraints or counterexamples to properties.checked 4 Oct 2026
- Release
- The site lists Alloy 6.2.0 as the latest release, dated 2025-01-09.checked 4 Oct 2026
- Security use
- The project says Alloy has been used to find holes in security mechanisms and describes modeling security configurations of web applications as an example.checked 4 Oct 2026
- Temporal analysis
- Alloy 6 adds mutable state, temporal logic, and temporal model checking; the latter relies on NuSMV or nuXmv installed by the user and available in PATH.checked 4 Oct 2026
- Visualization
- The Analyzer displays structures graphically, and their appearance can be customized for the domain.checked 4 Oct 2026
- Visualizer extension
- Sterling is a web-based Alloy visualizer customizable and extendable with JavaScript, with graph and table views.checked 4 Oct 2026
Where it runs
- Applications
- The project links applications including Alloy*, a Ruby embedding, a bounded Java verifier, and a firewall security policy analyzer.checked 4 Oct 2026
- Platforms
- The download page identifies Alloy 6.2.0 and says it includes a version for macOS High Sierra; it also describes running the JAR with Java.checked 4 Oct 2026
