Threagile

Threagile is an open-source threat-modeling toolkit for engineering teams that want architecture and security checks to live with code. It suits DevSecOps groups comfortable maintaining YAML in Git and automating analysis in repositories. Its main advantage is repeatable, version-controlled risk work; teams wanting a finished visual editor should choose another tool.

Overview

Threagile represents architecture and assets in YAML, then evaluates that model against risk rules. This code-oriented method makes threat analysis reviewable alongside architecture changes and gives teams a durable record instead of a one-off diagram. The project says its current UI efforts are still not ready, so YAML remains the primary working surface. A playground can analyze a model and provide links to schema and API resources, but it is not a substitute for a polished visual modeling application.

The software is open source under the MIT License and is maintained as a developer-friendly toolkit for agile projects and DevSecOps workflows. Support is community-based: users can open a GitHub discussion or issue for contributor responses.

Key features

Risk analysis and remediation

Threagile produces reports of potential risks together with recommended mitigation actions. It also generates data-flow diagrams automatically and exports results in formats including Excel and JSON. That combination is practical for teams that need both machine-readable output for automation and shareable artifacts for reviews.

Mitigation status can be recorded directly in the YAML model, allowing reports to show the current state of remediation. This turns threat modeling into an ongoing engineering record rather than an assessment that goes stale after its first workshop.

Developer workflow and extensibility

Models are editable in developer IDEs and diffable in Git, so changes can be reviewed with familiar source-control practices. The toolkit runs from the command line, in Docker, or as a REST server. Its GitHub Action can run Threagile against a model file in a repository, making it suitable for repeatable checks in a delivery workflow.

Risk rules can be customized as YAML scripts without compiling Go code. That lowers the barrier for teams whose architecture or policy needs do not fit a fixed ruleset, while still keeping those rules reviewable as text. Templates and frameworks are supported, and the modeling method is custom rather than tied to a single prescribed notation.

Pricing

There is no paid tier, seat charge, usage quota, or trial period attached to the published plan. The free distribution suits teams able to run and maintain an open-source tool themselves. It gives up the expectations that come with a commercial service, such as a ready UI and vendor-backed support; the project instead directs users to GitHub discussions and issues.

Platforms

Threagile supports API, Linux, self-hosted, and web deployments. Command-line, Docker, and REST-server execution provide deployment flexibility, while the GitHub Action covers repository automation. Its self-hosted and developer-tool orientation is a better match for teams controlling their own environment than for buyers seeking a hosted, turnkey workspace.

Who it's for

Choose Threagile if developers, architects, and security engineers can maintain YAML models, review diffs in Git, and incorporate risk checks into CI or other automation. It is particularly well suited to agile and DevSecOps teams that need custom rules, explicit mitigation tracking, and exports for downstream reporting.

It is a poor fit for stakeholders who expect to create and maintain models primarily through a finished drag-and-drop interface. The stated UI status means teams must accept the text-first workflow rather than treating it as an optional technical mode.

Pros and cons

Pros

• Version-controlled modeling: YAML files can be edited in IDEs and diffed in Git, making architectural security changes reviewable.
• Actionable reporting: risk findings include recommended mitigations, with diagrams and Excel or JSON exports for communication and automation.
• Persistent remediation state: mitigation status in the model keeps reports aligned with current work.
• Automation options: CLI, Docker, REST, and a GitHub Action support local, service-based, and repository workflows.
• Rule customization: YAML scripts let teams add risk logic without compiling Go code.

Cons

• UI is not ready: teams seeking visual-first authoring must work around the YAML-centered process.
• Self-managed operation: deployment and support are oriented around running the open-source project and using GitHub discussions or issues.

Alternatives

CAIRIS is another free option with API, web, desktop, and self-hosted platform coverage, including Windows and macOS. OWASP Threat Dragon is free and open source with Linux, macOS, Windows, web, and self-hosted support and no stated paid plans or usage limits. pytm is a free choice for teams wanting a cross-platform desktop threat-modeling option backed by an OWASP open-source project. ThreatForge is free, open source under Apache 2.0, requires no account, and runs on Linux, macOS, Windows, and the web.

IriusRisk suits readers who want a freemium product with a Community Edition limited to three active threat models and one user with limited collaboration, plus templates and XML diagram export. ThreatModeler Nexus offers a free Community Edition for practitioners and teams evaluating threat modeling before scaling to paid licensing. ThreatOpus is the better choice when a hosted freemium service, 15 users, 10 workspaces, repository connections, and monthly generation quotas justify its £129.99/month Starter plan. ThreatTree fits users who prefer explicit tree and diagram caps on a free plan or unlimited forests on its $29.00-per-user monthly Pro plan.

Browse more options in Threat Modeling Software.

Verdict

Threagile is a strong choice for developer-led security programs that want custom, Git-friendly threat models, automated risk reports, and mitigation tracking without a license fee. Choose it for repeatability and integration flexibility. Look elsewhere if your priority is a mature graphical interface or a commercially managed support experience.