pytm

At a glance

• Editor score
  7.3 / 10
• Pricing
  Open source
• Best for
  Developers who prefer code-defined threat models
• Paid from
  Free
• Facts checked
  22 Sep 2026

• Where it wins

  • Defines threat models in Python for development-focused workflows
  • Generates data-flow diagrams, sequence diagrams, reports, and findings
  • Supports custom threats, rules, templates, and JSON exchange

• Where it doesn't

  • Self-hosted deployment requires teams to manage the local environment
  • Does not provide verified collaboration or attack-path analysis
  • Broader integrations are limited compared with wider platform offerings

Our verdict on pytm

pytm is an open-source threat-modeling framework from OWASP for developers and security practitioners who want to define system architecture in Python. Instead of working through a hosted visual workspace, users describe model elements and properties in code, then generate data-flow diagrams, sequence diagrams, reports, and threats relevant to the modeled system. It runs on Windows, macOS, and Linux, making it a fit for teams that want threat modeling close to development workflows and source-controlled artifacts.

The main strength is depth within a code-defined approach. pytm can automatically generate threats and findings, produce risk-colored diagrams, and use templates for threat-model reports. Custom threat files and threat rules allow teams to shape the output around their own modeling needs, while JSON import and export supports exchange between workflows. These capabilities make pytm more adaptable than a fixed checklist, particularly for developers who prefer repeatable definitions and generated documentation over manual diagram editing.

Its trade-off is focus. pytm is distributed as open-source code and uses self-hosted deployment, so it is better suited to teams comfortable managing a local or containerized runtime than to organizations seeking a hosted collaborative application. The published feature set also does not include verified collaboration, attack-path analysis, or broad integrations. Choose pytm when Python-defined models, generated diagrams, custom rules, and local control are priorities. Consider an alternative when nontechnical stakeholders need built-in collaboration or when attack-path analysis and a wider integration ecosystem are central requirements.

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pytm pricing

pytm fact sheet

Alternatives to pytm

• CCAIRISA broad open-source choice for teams connecting threats, requirements, architecture, and risk.9.4
• IriusRiskA flexible threat-modeling platform with automation, integrations, and a useful free tier.9.3
• ThreatModeler NexusAI-assisted threat modeling with attack paths, risk prioritization, compliance, and CI/CD checks.9.2

See all pytm alternatives →

Featured on iTechGuides

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update