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Alloy Analyzer
What Alloy Analyzer is
Alloy Analyzer is a free tool for describing and exploring structures with the Alloy language. You specify constraints, and the Analyzer searches for structures that meet them or counterexamples to properties. Models can represent systems that evolve, including security configurations and switching network topologies. The Analyzer displays results graphically, with appearances that can be adapted to a domain. Alloy 6 adds mutable state, temporal logic, and temporal model checking; using the model-checking option requires NuSMV or nuXmv installed and available in PATH. The 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 incorporated into other applications as an API. Sterling is a web-based visualizer with graph and table views that can be extended with JavaScript. Alloy supports invariant verification and counterexample generation and runs on Linux, macOS, and Windows. The project originated in MIT's Software Design Group and is maintained by volunteers, with Discourse and Stack Overflow serving as community discussion venues.
Who it suits
Alloy Analyzer suits people modeling constrained systems and checking properties, including those working with security configurations or changing network topologies. It is relevant to users who can work with the Alloy language and, for temporal model checking, install NuSMV or nuXmv.
What it does well
- Free, self-contained executable includes examples and source.
- Finds structures and counterexamples to properties.
- Graphical results can be customized.
- JAR can be used as an API.
What to know first
- Temporal model checking requires NuSMV or nuXmv.
- Those temporal tools must be available in PATH.
- Modeling uses the Alloy language.
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Alloy Analyzer | Open source project · self-contained executable | Free |
As alloytools.org lists them, read 4 Oct 2026. The maker's own page has the final word.
Getting started
- Visit the Alloy website.
- Use the self-contained executable on Linux, macOS, or Windows.
- Explore the included standard library, tutorial examples, and source code.
- Install NuSMV or nuXmv and make it available in PATH if using temporal model checking.
- Use the JAR in another application if you need Alloy as an API.
Verdict
Alloy Analyzer combines constraint-based model exploration with graphical views and counterexample generation. Temporal model checking adds a separate installation requirement, so users should account for NuSMV or nuXmv when planning that workflow.
Questions
How much does Alloy Analyzer cost?
The listed plan is free.
Which platforms are supported?
The listed platforms are Linux, macOS, Windows, and API.
What can Alloy Analyzer verify?
It supports invariant verification through model checking and can produce counterexamples.
What is required for temporal model checking?
Alloy 6 temporal model checking relies on NuSMV or nuXmv installed by the user and available in PATH.
Can Alloy be used from another application?
Yes. The same JAR file can be incorporated into other applications as an API.
Who created Alloy?
Alloy was created in MIT's Software Design Group and is maintained by volunteers.
Facts from Alloy Analyzer's own pages
- API
- The same JAR file can be incorporated into other applications to use Alloy as an API. · alloytools.org, 4 Oct 2026
- Applications
- The project links applications including Alloy*, a Ruby embedding, a bounded Java verifier, and a firewall security policy analyzer. · alloytools.org, 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. · alloytools.org, 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. · alloytools.org, 4 Oct 2026
- Modeling
- Alloy models describe sets of structures that may evolve over time, such as security configurations or switching network topologies. · alloytools.org, 4 Oct 2026
- Origin
- Alloy was created in MIT's Software Design Group. · alloytools.org, 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. · alloytools.org, 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. · alloytools.org, 4 Oct 2026
- Release
- The site lists Alloy 6.2.0 as the latest release, dated 2025-01-09. · alloytools.org, 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. · alloytools.org, 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. · alloytools.org, 4 Oct 2026
- Visualization
- The Analyzer displays structures graphically, and their appearance can be customized for the domain. · alloytools.org, 4 Oct 2026
- Visualizer extension
- Sterling is a web-based Alloy visualizer customizable and extendable with JavaScript, with graph and table views. · alloytools.org, 4 Oct 2026
Where Alloy Analyzer stands on Freedom251
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